Le Réseau BIO

Plate-forme de réseautage pour les producteurs, transformateurs et commerçants d'aliments biologiques du Québec
Le Réseau BioUn site réalisé grâce à un partenariat
CETAB+ | Centre d'expertise et de transfert en agriculture biologique et de proximitéMinistère de l'Agriculture, des Pêcheries et de l'Alimentation du Québec
Bienvenue sur le Réseau BIO, une plate-forme de réseautage pour les producteurs, transformateurs et commerçants d'aliments biologiques et intervenants en agriculture biologique au Québec.

Modifier eXtension Articles,News,Faqs,Events- organic production (anglais)

S'abonner à flux Modifier eXtension Articles,News,Faqs,Events- organic production (anglais)
Mis à jour : il y a 2 heures 44 min

Organic Tomato Foliar Pathogen IPM Webinar

mar, 2017/12/12 - 15:41

Join eOrganic for webinar on how to manage foliar pathogens organically! Effectively managing foliar pathogens is one of the biggest challenges facing organic tomato growers. This webinar will provide an overview of practices that can help synergistically address this challenge. Topics will include starting with a strong foundation by building and maintaining soil health, selecting the right varieties, cultural practices that make the environment less favorable for pathogens, disease identification and management using organic fungicides. The webinar takes place on March 21, 2018 at 2PM Eastern Time, 1PM Central, 12PM Mountain, 11AM Pacific. It's free and open to the public, and advance registration is required. 

Register now at https://attendee.gotowebinar.com/register/2084653542898832897

Presenters: Dr. Dan Egel, Vegetable Pathology Extension Specialist, Dept. of Botany and Plant Pathology, Purdue University; Dr. Lori Hoagland, Associate Professor, Dept. of Horticulture, Purdue University; Dr. Amit-Kum Jaiswal, Postdoctoral Research Associate, Dept. of Horticulture, Purdue University

System Requirements

View detailed system requirements here. Please connect to the webinar 10 minutes in advance, as the webinar program will require you to download software. To test your connection in advance, go here. You can either listen via your computer speakers or call in by phone (toll call). Java needs to be installed and working on your computer to join the webinar.  If you are running Mac OSU with Safari, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar, and if it isn't working, try Firefox or Chrome.

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 24154

Conducting On-Farm Variety Trials to Manage Risk for Organic and Specialty Crop Producers

mar, 2017/12/12 - 12:55

Join eOrganic for a 2-part webinar on how to conduct on-farm variety trials to reduce risk on organic and specialty crop farms. The goal of this two-part webinar series is to provide horticultural crop and small grain growers with the skills and information necessary to conduct effective on-farm trials, and manage risk in crop variety and seed sourcing decisions. These webinars include new perspectives from organic certifiers, updated methods for conducting simple and effective on-farm trials, and an introduction to new user-friendly online data analysis tools. This webinar series is open to all, but most appropriate for growers with at least two seasons of production experience. The webinars take place on March 20 and April 11, 2018, and they are free and open to the public. Advance registration is required.

Register just once to attend both webinars at https://attendee.gotowebinar.com/register/8859858486902985985

About the Webinars

Identifying optimum genetics through variety trials is an important risk management tool for organic producers. Well-suited varieties provide farmers with crops that perform optimally in particular climatic and management conditions, withstand pest and pathogen pressure, and meet market demands. These webinars are offered through a collaboration between Organic Seed Alliance, University of Wisconsin- Madison, Midwest Organic and Sustainable Education Service (MOSES), and the United States Department of Agriculture’s Risk Management Agency. 

Webinar 1: Trial planning, planting, and management. March 20, 2018

This webinar will introduce farmers to the practice of variety trialing, detailing the reasons one might choose to conduct trials and how to plan a trial with a scope, scale, and focus appropriate to the growers’ needs. This session will also cover seed sourcing, and important considerations for trial planting and management.

Webinar 2: Trial evaluation, analysis, and interpreting results. April 11, 2018

This webinar will focus on record-keeping and trial evaluation, as well as analysis and interpretation of final results. This session will introduce participants to some intuitive techniques for keeping data organized, and user-friendly online tools to aid in analyzing information collected and drawing conclusions from trial results.

About the Presenters

Micaela Colley is the Program Director of the Organic Seed Alliance. She leads OSA’s research and education programs focused on organic seed production and organic plant breeding.

Dr. Julie Dawson,Assistant Professor, University of Wisconsin- Madison. She is Assistant Professor for Urban and Regional Food Systems in the Department of Horticulture at UW-Madison. Her research focuses on variety trialling and breeding for organic systems in the upper Midwest.

Jared Zystro, Research and Education Assistance Director, Organic Seed Alliance. Jared manages regional organic seed system development in California, conducts participatory breeding projects and variety trials, and teaches farmers about seed production and plant breeding at workshops, conference, and field days, and collaborates on other projects throughout the country.

Kitt Healy, Midwest Research and Education Associate, Organic Seed Alliance. Kitt manages OSA’s research and education programming in the Midwest region, and is an outreach associate in Dr. Julie Dawson’s lab at UW-Madison.

This material is funded in partnership by USDA, Risk Management Agency, under award number RM17RMEPP522C027/4500075447.

System Requirements

View detailed system requirements here. Please connect to the webinar 10 minutes in advance, as the webinar program will require you to download software. To test your connection in advance, go here. You can either listen via your computer speakers or call in by phone (toll call). Java needs to be installed and working on your computer to join the webinar.  If you are running Mac OSU with Safari, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar, and if it isn't working, try Firefox or Chrome.

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 24153

Organic Tomato Seed Production Webinar

mar, 2017/12/12 - 12:08

Join eOrganic for a webinar on organic tomato seed production on January 30, 2018 at 2PM Eastern Time (1 Central, 12 Mountain, 11 Pacific). The presenters are members of a NIFA OREI funded project entitled Tomato Organic Management and Improvement. The webinar is free and open to the public, and advance registration is required. 

Register now at: https://attendee.gotowebinar.com/register/3337021476188146690

About the Webinar

Tomato is one of the most popular fresh market vegetables, with a rich assortment of varieties that vary in appearance, flavor and agronomic properties. Learning how to produce your own seed will help ensure that your favorite varieties will continue to be available and passed on to future generations. This webinar will provide an overview of practices needed to successfully produce quality organic tomato seed. Key topics will include varietal considerations, isolation and management practices, and fermentation, storage and treatment practices that will maintain seed integrity and help reduce pathogen transmission.

Presenters

Julie Dawson, Assistant Professor, Dept. of Horticulture, University of Wisconsin-Madison; Dan Egel, Vegetable Pathology Extension Specialist, Dept. of Botany and Plant Pathology, Purdue University; Laurie McKenzie, Research and Education Associate, Organic Seed Alliance. Learn more about the Tomato Organic Management and Improvement project at https://eorganic.info/tomi

System Requirements

View detailed system requirements here. Please connect to the webinar 10 minutes in advance, as the webinar program will require you to download software. To test your connection in advance, go here. You can either listen via your computer speakers or call in by phone (toll call). Java needs to be installed and working on your computer to join the webinar.  If you are running Mac OSU with Safari, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar, and if it isn't working, try Firefox or Chrome.

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 24151

Abrasive Weeding: Efficacy, Multifunctionality, and Profitability

jeu, 2017/11/30 - 15:33

Join eOrganic for a new webinar on abrasive weeding by Sam Wortman of the University of Nebraska-Lincoln The webinar takes place on March 29, 2018 at 2PM Eastern, 1PM Central, 12PM Mountain and 11AM Pacific Time. The webinar is free and open to the public and advance registration is required.

Register now at  https://attendee.gotowebinar.com/register/3758336739503684611

About the Webinar

Small grits propelled by compressed air can be used to abrade weed seedlings within crop rows. This non-chemical weed management tactic is called abrasive weeding, and our research team has been developing new grit application technologies, exploring multifunctional grit sources, and studying effects of air-propelled grits on a diversity of weeds and crops throughout the Midwest. In this webinar, we will present results from over three years of research and development, and discuss opportunities for maximizing weed control, crop nutrition and yield, and profitability with abrasive weeding. eOrganic hosted an introductory webinar about this topic in 2015, available here, and this presentation will add new information.eOrganic also published an article and video about abrasive weeding, available here.

System Requirements

View detailed system requirements here. Please connect to the webinar 10 minutes in advance, as the webinar program will require you to download software. To test your connection in advance, go here. You can either listen via your computer speakers or call in by phone (toll call). Java needs to be installed and working on your computer to join the webinar.  If you are running Mac OSU with Safari, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar, and if it isn't working, try Firefox or Chrome.

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 24056

November 2017

lun, 2017/11/27 - 11:08
New eOrganic Article: Spotted Wing Drosophila: Biology, Behavior and Organic Management 

This article, by Andrew Petran of the University of Minnesota examines the biology and management of spotted wing drosophila (SWD), Drosophila suzukii, within organic farming systems. Read the most up-to-date information on SWD management strategies from a multi-university study funded by NIFA OREI. Read the article here

New Video: Managing Cucurbit Downy Mildew on Organic Farms:

This new video will help you identify cucurbit downy mildew, learn which cultivars provide you with protection and which organic chemical controls might be appropriate for your production. It will also provide some tips on how to grow cucumbers under high tunnels and link to some blueprints for high tunnel design. The video was .created by Rachel Hultengren of Cornell University is from the NIFA OREI funded Eastern Sustainable Organic Cucurbit Project, led by Michael Mazourek. Watch the video here

2016 Cucurbit Trial Results Available

The Eastern Sustainable Organic Cucurbit Project has also published its trial results for 2016, from research farms in Alabama, North Carolina, South Carolina and New York. Researchers looked at the yield and resistance to various diseases of a variety of cucumbers, melons and summer squash. Find the 2016 report here, and find the report from 2014-15 here

New Organic Melon Webinar

Join eOrganic for a webinar on organic melon production: best practices, microbial safety and consumer preferences, by Shirley Micallef and Kathryne Everts of the University of Maryland. The webinar takes place on January 31 2017 at 2PM Eastern Time, 1PM Central, 12PM Mountain, 11AM Pacific Time. Find out more and register at http://articles.extension.org/pages/74584

Take our Online Organic Information Survey

If you didn't take this survey last month, please click the link below! We, the eOrganic staff and leadership team, are interested in learning more about your interests in certified organic agriculture to guide the development of eOrganic content. The survey will take about 3-5 minutes. Please give us your recommendations for future development of eOrganic online resources by answering the questions below. Please answer thoroughly, and honestly, to help us improve our information resources. There are no foreseeable risks associated with participation. Your participation is entirely voluntary; there will be no penalty if you choose not to participate or not to answer specific questions. Completion of the survey indicates that you have read and understood this description and agree to participate. Funding for this survey is provided by NIFA grants awarded to Oregon State University, Cornell University, University of Minnesota, University of Illinois, Purdue University, University of Georgia, Utah State University, Washington State University, Tuskegee University, the USDA-ARS, and the Organic Seed Alliance. Take the survey here!

Recordings available: Organic Soil Health Special Session

Recordings from the recent Special Session at the Tri-Societies Conference on organic soil health are now conveniently available as a YouTube playlist here. The following presentations are available:

Organic Seed Growers Conference

Registration is now open for the 9th Organic Seed Growers Conference, which is the largest organic seed event in the U.S. You’ll hear the latest in cutting-edge research and policy advocacy, and trade knowledge, techniques, and ideas with other seedheads from around the world. The conference provides a full agenda of presentations, panel discussions, and networking events. The first two days include farm tours and short courses prior to the full conference. The theme for 2018 is Synergy that Sustains, reflecting an emphasis on developing networks for research, education, and advocacy, and supporting a diversity of approaches to advancing organic seed systems. Find out more and register here

Our Farms, Our Future Conference

hosted by the Sustainable Agriculture Research and Education (SARE) program and the National Center for Appropriate Technology ATTRA program will be held on April 3-5, 2018 in St. Louis, Missouri. This national event will bring together a diverse agricultural community including farmers and ranchers, agribusiness stakeholders, students, researchers, scientists, agency representatives and nonprofit leaders. Every decade SARE hosts a conference to look at the progress of sustainability in agriculture and to understand its  trajectory for the future. Find out more and register here

eOrganic Mission

eOrganic is a web community where organic agriculture farmers, researchers, and educators network; exchange objective, research- and experience-based information; learn together; and communicate regionally, nationally, and internationally. If you have expertise in organic agriculture and would like to develop U.S. certified organic agriculture information, join us at http://eorganic.info.

eOrganic Resources

eOrganic logo

 

 

 

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23936

Melon Medley: Organic Production Practices, Microbial Safety and Consumer Preferences of various Melon Varieties

mer, 2017/11/22 - 14:18

Join eOrganic for a webinar on organic melon production: best practices, microbial safety and consumer preferences, by Shirley Micallef and Kathryne Everts of the University of Maryland. The webinar takes place on January 31 2017 at 2PM Eastern Time, 1PM Central, 12PM Mountain, 11AM Pacific Time.

Register now at: https://attendee.gotowebinar.com/register/3302866246541722626

About the Webinar

Melon (Cucumis melo subsp. melo) is a valuable commodity, but production in Maryland has significantly decreased over the last twenty years. Declines in production can be attributed to several factors including disease and pest susceptibility, labor demands, increased market competition, and frequent implication in multistate foodborne disease outbreaks and recalls. Moreover, although consumer demand for organically-cultivated fruit continues to rise steadily every year, organic melon systems in the hot, humid climate of Maryland present unique challenges in the form of pest management and crop protection. To better understand how organic production practices may not only improve yield and fruit quality, but also decrease food safety risk, several melon varieties were grown using tilled single and two-species green manures in organic and transitional systems. Melon yield, disease incidence, melon sensory qualities and transmission of foodborne indicator bacteria onto fruit were assessed. Different melon cultivars grown in various green manures were transported to the lab for evaluation of their susceptibility to human pathogen colonization. Data on best production practices, microbial safety and consumer preference of various melon cultivars can provide farmers with applicable information to improve profitability of this valuable crop. This webinar will present results and discuss successes and challenges experienced throughout this three year study, funded by USDA NIFA through the Organic Transitions Program.

About the Presenters

Dr. Shirley Micallef is an Associate Professor at the University of Maryland Department of Plant Science and Landscape Architecture. Her research focuses on the microbiological safety of fresh produce. 

Dr. Kathryne Everts is a Professor and Extension Specialist at the University of Maryland Lower Eastern Shore Research & Education Center  She conducts research on the epidemiology and management of vegetable diseases that are economically important in the mid-Atlantic region.Currently her lab focuses on the soilborne diseases Fusarium wilt on watermelon, and white mold on lima bean; Fusarium fruit rot on melon, and the foliar diseases cucurbit downy mildew and powdery mildew. 

System Requirements

View detailed system requirements here. Please connect to the webinar 10 minutes in advance, as the webinar program will require you to download software. To test your connection in advance, go here. You can either listen via your computer speakers or call in by phone (toll call). Java needs to be installed and working on your computer to join the webinar.  If you are running Mac OSU with Safari, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar, and if it isn't working, try Firefox or Chrome.

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23948

Managing Cucurbit Downy Mildew on Organic Farms

mar, 2017/11/21 - 17:07

eOrganic author:

Rachel Hultengren, Cornell University

Video Transcript

This video will focus on managing cucurbit downy mildew on organic farms. Downy mildew (caused by the oomycete Pseudoperonospora cubensis) has always been a disease of cucurbit crops. There are other downy mildews that affect other crops, but these generally cannot also infect cucurbits.

Dr. Michael Mazourek (Cornell University, Plant Breeding & Genetics Section): This is the characteristic symptom of downy mildew on cucumber. A lot of cucurbits get downy mildew, but the symptoms are very obvious on cucumber. It's this kind of quilted appearance on the top, and on the bottom is where you see the reason it has its name. There are these black spores underneath the yellow regions. If there's any uncertainty, you could put a leaf in a wet paper towel overnight, and see if it starts to sporulate, but if it's wet like in this high tunnel, there's no need to do that—you'll see the sporulation right away.

Downy mildew is particularly severe when the crop experiences alternating wet-dry cycles, as these are needed by the pathogen to reproduce and infect new hosts via airborne spores. If you have questions about whether your crop has downy mildew, you can consult a plant pathologist at your local land grant university.

Dr. Michael Mazourek: This leaf has a mixed infection—multiple pathogens are affecting it. We can see there's some downy mildew affecting it, and confirm that by seeing the quilted regions, the squares of the downy mildew spores on the back, that are black. It also has Alternaria. It would be hard to tell for sure that this is Alternaria, without actually looking at the spores under a microscope—like your local diagnostic lab might be able to help you with—but this is also, I know, a cultivar that's susceptible to Alternaria, and the cultivar we were just looking at before is not susceptible (it's resistant) to Alternaria, so that makes this quite a telling diagnosis.

As you are getting some diagnostics done, it's important to have a leaf just in the initial stages, because you'll have secondary infections moving in that are taking advantage of the diseased plant. So if you were to provide a sample like this to your diagnostic lab, there's just so much going on and taking advantage of the infected plant tissue that you can't really tell what was the cause—there are many other pathogens moving in and further colonizing this leaf that aren't necessarily the ones that caused it to die.

Zaid Kurdieh (Norwich Meadows Farm, Norwich, NY): At Norwich Meadows Farm, the cucumber crop is definitely the most difficult crop for us to take care of because of pests and diseases. It seems like downy mildew is getting worse and worse every year. We're getting it, it seems like, earlier and earlier; it did not used to be as bad years ago—say ten years ago.

Until 2004, downy mildew-resistant varieties of cucumber were commercially available and widely used. In 2004, the disease changed radically, and cultivars that were resistant to the old strain are now susceptible.

This video will provide information about finding cultivars that are resistant to this new strain, and the timing, chemical, and cultural strategies that you can use to reduce your losses due to cucurbit downy mildew.

There are currently very few choices for downy mildew-resistant cucumber cultivars. Some Asian-type cucumbers, like Suyo Long, tend to have usable resistance. In slicing cucumbers, there are cultivars with moderate to high levels of resistance coming out of the Cornell University program: Marketmore 97, Marketmore 420, and more recent releases DMR-264 and DMR-401.

Melon is the second most susceptible cucurbit to downy mildew. The Mazourek program at Cornell has identified resistant cultivars that are older, like Seminole, and developed a new cultivar, Trifecta, that's also commonly available. Hopefully, there will be many more choices in the future. While summer squash is the least susceptible to downy mildew, it can still suffer significantly.

It is important to remember that if you're growing both susceptible and resistant cultivars, or if you're growing a highly susceptible variety upwind of your resistant variety, the resistant cultivar can be overwhelmed. This high tunnel, for example, is downwind of an infected field of a susceptible variety of squash, so the cucumbers inside are being exposed to high levels of the airborne spores. Plan to grow susceptible cultivars downwind of resistant ones.

You need only use resistant cultivars when you know you are at risk for the pathogen. CDM IPM Pipe is a helpful website that provides forecasting information, and histories of when the disease has arrived in certain areas. Importantly, it can advise to the vulnerability of your crop (given your location), so you can learn how to time your interventions during times when the pathogen is likely to be in your area.

Knowing when you typically need to use a resistant cultivar can be a useful strategy for your farm. You should know that when you are working with resistant cultivars, there are often trade-offs for agronomic or quality characteristics. As you can see in this graph, there are many other great varieties to grow earlier in the season, when cucurbit downy mildew is not a problem. Use resistant cultivars when and where appropriate.

One OMRI-listed pesticide that has been shown to be an effective and therefore potentially useful tool for controlling cucurbit downy mildew is Zonix™, a rhamnolipid biosurfactant that kills zoospores.

For more information about Zonix™ and a variety of other chemical control methods, consult up-to-date resources as people explore the best ways to integrate biological and chemical controls.

NOTE: Before applying ANY product, be sure to 1) read the label to be sure that the product is labeled for the crop you intend to apply it to and the disease you intend to control in your state and local area, and 2) make sure that the brand name product is listed your Organic System Plan and approved by your certifier. For more information see Can I Use this Product for Disease Management on my Organic Farm?

Zaid Kurdieh:  Zonix™ definitely helps. This year, I think, because of the intense pressure, certain cultivars succumbed, they just couldn't handle it; the pressure was way too high.

Increasingly, growers are using high tunnels to have more control over their growing environment.

There are different designs of high tunnel, and differences in architecture affect the conditions inside. Gothic high tunnels, where trellises are hung from the rafters and humidity can be controlled through gable end vents, tend to be much drier. Under drier conditions, downy mildew cannot reproduce, so if your high tunnel design allows you to control humidity and leaf wetness, you'll be able to control downy mildew more effectively. Rounded high tunnels tend to be more humid than vented gothic high tunnels, but are still a more controlled environment than the field.

Even in a high tunnel, downy mildew can establish itself, leading to crop loss. In the drier high tunnels, we typically see the disease on the perimeter, where the plants are subject to outside conditions.

Because high tunnels change the environment, growing in a high tunnel requires varieties that are well suited to high tunnel production. If the high tunnel is being used to exclude striped cucumber beetles and other pests, it will be necessary to grow parthenocarpic cultivars that do not require pollination to set fruit, such as Beit-alpha cucumbers. Seed catalogues will include the term parthenocarpic in their descriptions—look to determine whether netting the high tunnel will be useful or detrimental based on the cultivar you're growing.

In a high tunnel, with increased transpiration, there can be an increased severity of wilt pathogens that might not be a problem outdoors in the Northeast, such as bacterial wilt.

Dr. Michael Mazourek: Here is a cucumber suffering from bacterial wilt. It is a bacterium transmitted by striped cucumber beetles—as they feed they'll infect the plant—and you have this appearance very much like the plant is shutting like an umbrella. Also accompanied with it, you can see in this leaf symptom here, is that there will be this browning between the major veins in the leaves that often accompanies it. There are many other wilts that can affect a cucumber plant, but bacterial wilt is by far the most common, especially in high tunnels, in my experience.

There is one bacterial wilt-resistant cucumber cultivar: please contact Dr. Michael Mazourek at Cornell University if you are interested in growing this variety.

There are a few considerations to keep in mind when growing under high tunnels. First, it is a good idea to rotate crops in your high tunnel to break up disease cycles.

Zaid Kurdieh: Those rotations are critical. Rotations are very, very critical.

Growing a wide range of crop families can make a significant difference in disease pressure, and be a valuable tool in soil fertility management. Nutrient management requires greater attention under high-tunnel cultivation, as the lack of soil exposure to rain can facilitate the buildup of soluble salts.

One way to address this is to have a rolling high tunnel, like this one at Cornell's Dilmun Hill student farm. The rails allow the tunnel to be moved from one field to another; this way, one plot is exposed to precipitation every 6 months, allowing salts to leach more effectively from the soil.

Alena Hutchinson (Cornell University, Mechanical and Aerospace Engineering '18): Here at Dilman Hill, we have a movable high tunnel. It's just like a traditional high tunnel, but it's on a set of rails, and the tunnel itself is mounted on pipe-gate rollers, which are actually used in chain-link fences. And that allows the tunnel to be moved by just one or two people from one site to another.

The plot that's uncovered by the high tunnel is exposed to the elements, and also, generally, we have a cover crop planted there. And what that does is while your cover crop is replenishing the good nutrients that you do want your plants to have for the next season, the rain and snow and other elements that that side is exposed to, (it) has kind of the buildup, that you don't want, washed away.

We designed the high tunnel here at Dilman Hill, and the blueprints are freely available on our website.

You can also look at the economic analysis tool that we've developed to help you consider the costs and benefits of these interventions. It will be hosted here on the resource page of the Eastern Sustainable Organic Cucurbit Project.

In the end, you'll have the best results when you combine all of these practices into a holistic strategy for managing cucurbit downy mildew. Understanding when your farm is at risk, which cultivars provide you protection and when to use them, which chemical controls might be appropriate for your production, and how to grow cucumbers under high tunnels, can all increase your ability to successfully manage the disease on your organic farm.

Many thanks to the USDA's National Institute of Food and Agriculture for supporting this work.

Additional Resources

High Tunnel Blueprints:

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23927

Spotted Wing Drosophila: Biology, Behavior and Organic Management

ven, 2017/11/17 - 18:08

eOrganic author:

Dr. Andrew J. Petran, University of Minnesota

Introduction

This article examines the biology and management of spotted wing drosophila (SWD), Drosophila suzukii, within organic farming systems. Information compiled in this article has been adapted from relevant publications and a recent two-year, multi-university study funded by the UDSA Organic Agriculture Research and Extension Initiative (OREI). More information on this project can be found on the Organic Management of Spotted Wing Drosophila Website or the recording of the recent webinar about SWD from February 2017. 

SWD Biology and Behavior 

Native to eastern Asia, SWD is an invasive fruit fly first discovered in 2008 on mainland United States. Mature adults are approximately 2.5mm in length, similar to a single raspberry drupelet. Male SWD have a distinguishable black spot on the first vein of their wings (Fig. 1a), and a black band on the first two tarsal segments of their forelegs. While harder to identify, females have a serrated ovipositor (Fig. 1b). This allows SWD to lay eggs within intact, still-ripening fruit.

 

Figure 1. Adult Spotted Wing Drosophila. (a) Male SWD; (b) Close-up of serrated ovipositor on female SWD. Photo Credits: (a) G. Arakelian, Oregon Department of Agriculture; (b) M. Hauser, California Department of Agriculture.

There are several fruit fly species with similar morphologic characteristics to SWD, most notably Drosophila subpulchrella, which also has dark wing spots. However, this fly is not present in the United States. While a specialist is typically needed for conclusive identification, a grower can reasonably identify SWD caught in traps using the reference traits described above. 

The common fruit fly, Drosophila melanogaster, is native to the United States and doesn't pose a significant economic threat to fruit growers. This is because it can only lay eggs in fruit that is either previously damaged or overripe, and thus already unmarketable. Due to the serrated ovipositor, SWD can pierce into the developing skin of intact fruit. This simple morphologic difference is why SWD poses such a threat to fruit producers nationwide (Fig. 2). 

Figure 2. A comparison of ovipositors between D. melanogaster and SWD. Photo credit: M. Hauser, California Department of Agriculture. 

Adult SWD prefer relatively cool and humid environments. They are most active at dawn and dusk, at temperatures ranging between 59 and 70 degrees Fahrenheit. As the end of the field season nears, SWD adults emerge as winter morphs, with different morphological characteristics. The bodies of winter morphs are distinctively darker in color, with larger wings. Research is ongoing to determine the ability of winter morphs to overwinter at cold temperatures and to travel long distances for migration. 

Life Cycle and Field Infestation 

Adult SWD prefers underripe, developing soft-skinned fruit for laying eggs. This includes raspberries, blackberries, blueberries, cherries, strawberries, and dozens of wild fruits found throughout the country. Asplen et al. (2015) provides a thorough description of the SWD life cycle: female SWD lay their eggs inside the fruit, which then develop into first, second, and third larval instar phases before pupation. Pupae can develop partially or completely outside of the fruit before emerging as adults (Fig. 3). Development rate is dependent on temperature, but a complete life cycle can occur in as little as 10 days, with up to 13 generations in a single field season. Adult female SWD are capable of laying over 300 eggs in a lifetime. 

Figure 3. SWD life cycle. Photo credit: UMass Extension. 

Initially, SWD infestation within fruit can be difficult to identify. Seemingly intact fruit will have an oviposition scar on the skin, with breathing tubes from the SWD egg extruding from the position of the scar (Fig. 4a). Eventually the area around the scar becomes soft and sunken as the larvae develop (Figs. 4b & 4e). Fruit will commonly fall off of the plant by the time pupation occurs, and can break apart when handled (Figs. 4c & 4f). SWD development within fruit occurs between 43 and 89 degrees Fahrenheit, with optimum development at 84° F (Asplen et al.). Adults emerge soon after pupation, and begin the next generational life cycle. Using 43° F as a lower threshold, the average developmental period for SWD eggs, larvae, pupae, and adults are 20, 122, 93 and 1,050 degree days, respectively (Kinjo et al.). 

Figure 4. SWD infestation development within cherry and blueberry. (a) Initial oviposition, (b) Larval development, (c) Pupation partially visible on fruit, (d) Intact fruit, (e) Partially sunken fruit indicating larval development, (f) Degraded fruit. Red arrows indicate location where SWD eggs were laid. Photo credit: M. Hauser, California Department of Agriculture and A. Sial, University of Georgia.

SWD presence in the field is dependent on environmental conditions. In geographic regions where temperatures rarely fall outside of developmental limits, SWD can be detected year-round. However, areas that experience midsummer highs above 90° F can expect SWD presence to fall during that time. Conversely, regions where winter temperatures are consistently below freezing will not typically support SWD, though occasional winter morphs (late-season SWD thought to be more cold tolerant) have been caught in Wisconsin and Minnesota as late as December. Whether these morphs are surviving in shelters or benefitting from an occasional milder winter has yet to be determined. Another open area of research is determining whether summertime SWD in northern regions are primarily overwintering, or migrating from more southern regions where winter temperatures are not fatal.

Lee et al. (2011) observed that most small-fruit crops become susceptible to SWD as they begin to turn color. If left unchecked, growers of mid-to-late season crops such as late season blueberry and primocane fruiting raspberry can expect up to 100% crop loss. Crop losses due to SWD have been estimated to cost up to $500 million annually in the western United States alone (Goodhue et al., 2011). 

Organic Management of SWD

Controlling SWD on farms is difficult due to their short generation time, wide host range, lack of natural predators, and even their hearty immune systems. Organic growers face an especially hard task, being constrained to control practices that are organically approved. This portion of the article will document current research and best practices for monitoring and controlling SWD in organic systems. 

SWD Traps

Proper SWD management first requires knowing when they are present on the farm. The most common method for detecting SWD presence is trapping. SWD traps are commercially available but can also be made by hand. Most traps consist of three parts: a perforated container, a lure to attract SWD inside the container, and soapy water that SWD will eventually drown in. Many commercial lures are organically approved and hang above the liquid inside the container, but homemade lures are also commonly made. Lure recipes involving yeast, apple cider vinegar and sugar dissolved in the trap water are available online. 

Figure 5. Commercial SWD trap hanging in St. Paul, MN. Photo credit: Andrew Petran.

Traps are typically checked once a week. Depending on the trap type, this will involve inspecting sticky cards for SWD or draining the liquid through a filter to separate the caught insects before inspection. The liquid is commonly replaced during this time as well.

SWD traps are important because they indicate when the pest is first present on the farm. However, once SWD presence has been determined, the usefulness of traps likely diminishes. There is little to no current data consistently linking SWD trap numbers to total presence in the field or fruit infestation levels (Asplen et al., 2015). This is confounded by the variable effectiveness of trap types and environments, making it difficult to establish trap threshold standards. Additionally, there is no evidence that SWD traps are an effective method for reducing overall SWD populations in the field. Thus, the labor and economic costs of maintaining SWD traps after their presence is first determined may be more than the potential benefit of leaving them for the extent of the season.

Note that SWD traps are not the same as attract-and-kill devices, a new possible management technique that will be discussed later in the document.

Phenology Management

Phenology management, or avoidance through early management, requires knowing when SWD first arrives in an area, and is thus informed by trapping. Essentially, this technique embraces the philosophy of ‘if you can't beat them, avoid them’. If a grower lives in an area where SWD is not present year-round, they may have the opportunity to grow crops with a fruiting window that does not correspond with peak SWD season. For example, a grower in southern Minnesota can plant early-season blueberries that mature in early July. Even though this fruit is susceptible to SWD infestation, they can harvest relatively risk free because SWD doesn't appear in high numbers in this environment until harvest is ending (Fig. 6). 

Figure 6. SWD presence and severity, along with common fruiting windows of several blueberry and raspberry cultivars in the Upper Midwest. Figure by Andrew Petran.

Note that phenology management will be more effective in areas where SWD populations vary over the year. Regions where SWD is present year-round will likely not benefit from this practice. SWD presence by region is outlined in Asplen et al. (2015), or can be determined by SWD trapping or contacting a local extension agent.

Organic Sprays

Only organically approved insecticides can be used for SWD control on organic land. Any product listed by the Organic Materials Review Institute (OMRI) can be used on organic land, as long as application guidelines are followed.

IMPORTANT: Before using any pest control product in your organic farming system:

  1. Read the label to be sure that the product is labeled for the crop and pest you intend to control.
  2. Read and understand the safety precautions and application restrictions.
  3. Make sure that the brand name product is listed in your Organic System Plan and approved by your USDA-approved certifier.

Organically-approved spray options for SWD control are limited, both in availability and effectiveness. A two-year, multi-university study funded by the OREI observed Entrust® SC as the most effective spray for SWD control, with Grandevo® also showing effectiveness controlling 3rd instar larvae within infested fruit (Fig. 7). Products known as adjuvants can be mixed with insecticides to increase their efficacy. These products may influence the effectiveness of sprays on SWD.

Figure 7. (a) Adult SWD mortality after being exposed to leaves containing insecticides immediately after spraying (blue bar), 3 days after spraying (orange bar) and 5 days after spraying (grey bar). (b) SWD Larval presence after fruit is exposed to insecticide treatments. Figures available on eOrganic webinar for organic management of spotted wing drosophila.

Current research is attempting to identify novel sprays and application strategies that are effective at controlling SWD in the field. This includes the use of biochemical pesticides that display reduced toxicity on pollinators, and non-nutritive sugars that may lead to increased SWD mortality.

Attract-and-Kill Devices

Attract-and-kill pest management tactics utilize attractants to bring a target pest into contact with a killing device, including traps. While SWD traps are useful for detecting initial SWD presence in the field, using them for management is difficult as multiple hundred traps per acre may be required. Attract-and-kill (AK) devices that work by luring SWD to an insecticide or other killing method may provide a lower maintenance approach for reducing SWD populations and thus infestation. They offer advantages over traditional spraying that include less pesticide use, pesticides being concentrated on the device instead of plant material or fruit, and combining the insecticide with attractants to promote oral intake.

One SWD AK device being evaluated is the attracticidal sphere. Laboratory and field trials have shown SWD have a strong preference for red-colored spheres (Rice et al., 2016). The devices consist of a hemispherical plastic base capped with a wax/sugar/insecticide mixture (Fig. 8). In laboratory trials, SWD that came into contact with spheres loaded with Entrust® for 5 minutes experienced 80% mortality, with 100% mortality after 24-hr exposure (Rice et al., 2017). The goal is to have commercially available attracticidal spheres in the future.

Figure 8. SWD AK devices (a) close up with SWD, and (b) deployed in the field. Photos by Kevin Rice, USDA-ARS.

More information on SWD AK can be found on the eOrganic webinar for organic management of SWD.

Pruning Management

Environmental research has observed that SWD are most active at dawn and dusk, preferring to stay in cool, moist, and shady areas during the day (Asplen et al., 2015). The interior plant canopy of most fruit crops can provide this environment, possibly making it easier for SWD by hiding within the very plants they infest. Research is underway to determine if intensive pruning techniques can alter the microenvironment to be less beneficial for SWD, thus reducing infestation. Research is being conducted in multiple states on blueberries, blackberries, and raspberries with three major pruning treatments: a grower standard prune, a light prune with ≈25% more canopy coverage, and a heavy prune with ≈25% less canopy coverage (Fig. 9). 

Figure 9. Pruning treatments on Minnesota blueberry plants. Photo by Andrew Petran.

In 2016, data indicated that while heavy pruning often results in reduced total yields, pruning treatments have little effect on cumulative SWD infestation. However, preliminary 2017 data on Minnesota blueberries suggest that a heavier prune can result in a higher proportion of fruit available at the beginning of harvest. This may have phenological effects, loading a higher proportion of fruit into a window when SWD is not present in the environment.

Another possible advantage of pruning is the effect it may have on other control methods, such as spraying. By reducing the total canopy area, heavier pruning could allow sprays to penetrate further into the interior of the plant, where SWD are known to typically gather during the heat of summer days.

Floor Management

As discussed earlier, fruit infested with SWD often falls to the ground before adult emergence. This can make sanitation difficult, but it also allows the opportunity to examine floor management as an SWD control technique. In 2016, the OREI SWD project researched the effects of different mulch types on within-fruit SWD development. Artificially-infested blueberries were placed in different mulch treatments (plastic landscape fabric, and organic mulching material such as wood chips or sawdust, depending on location) and analyzed for adult emergence in Oregon, Minnesota, Georgia, and Michigan. Berries were placed both on top and underneath the surface of each mulch type. It was observed that maximum temperature conditions underneath the surface of mulching materials were less than the maximum temperatures observed on top (Fig. 10). Correspondingly, these treatments also had higher levels of SWD emergence from fruit.

Figure 10. Average, maximum, and minimum temperature conditions of mulch treatments in Minnesota blueberry fields. Two 1-week trials were conducted.

If 2017 results are similar, these findings can help growers make more informed cultural practice decisions for SWD management. For example, infested fruit that falls onto black landscape fabric can be exposed to temperature conditions that inhibit adult SWD emergence. Also, a 2016 survey revealed that growers sometimes bury fallen fruit as a sanitation practice. However, these results imply that such a practice provides infested fruit with more ideal developmental conditions, and may actually increase SWD emergence and presence on the farm.

SWD Exclusion 

Exclusion management is the practice of creating a complete physical barrier around a crop. The barrier should restrict outside pests and pathogens from coming into direct contact with plant tissue, but also may alter environmental conditions around the crop. Growers may be hesitant to employ exclusion practices due to initial infrastructure costs and/or the notion of trapping pests within the barrier if they manage to migrate inside. However, OREI research has observed that this organic practice can be consistently effective at reducing SWD infestation in small fruits.

SWD exclusion can mean completely enclosing a crop in plastic or a fine mesh insect netting, but often involves both—constructing a plastic-covered high tunnel around a crop, and covering any entrances, exits and ventilation holes with insect netting that SWD cannot pass through (Fig. 11). This mesh can be found through several commercial sources. Nets with tighter weaves are often heavier and exclude more insects; 80-gram insect netting is recommended for excluding SWD.

Figure 11. Miniature plastic high tunnels capped with 80g insect netting on either side, Morris, MN. Photo credit: Andrew Petran.

Exclusion management has been shown to effectively reduce SWD presence and infestation of small fruits, even compared to conventional control options. In 2015, exclusion practices in Minnesota reduced SWD infestation of fall-bearing raspberries to ≈2%, compared to 80% infestation in uncovered plots, and 61% infestation in uncovered plots treated with conventional insecticides (Rogers et al., 2016). Netting has shown similar effectiveness in reducing SWD in blueberry (Cormier et al., 2015). 2016 OREI exclusion research conducted on raspberries, blueberries and blackberries in Michigan, Arkansas, and Minnesota all observed higher temperatures and lower humidity inside exclusion tunnels. These tunnels also had significantly lower SWD infestation and higher marketable yields compared to uncovered controls (Figs. 12a & 12b).

 

Figure 12. (a) SWD presence in exclusion and non-exclusion blueberries in Michigan, 2016. (b) Total yield and % marketable fruit of different blackberry exclusion treatments in Arkansas, 2016. Poly-covered tunnel refers to tunnels completely enclosed in plastic alone, whereas netted tunnel refers to complete enclosure in exclusion netting.

While OREI research has observed only increases in marketable yields in exclusion settings, there is a concern that exclusion techniques can reduce potential yields by restricting pollinator access to crops, in addition to SWD. A recently funded project by the Minnesota Department of Agriculture is researching the effect of introducing commercial bumblebees within exclusion tunnels for fall-bearing raspberry.

Conclusion

Like most invasive pests, SWD is a problematic insect in the United States. Its broad host range and lack of native predators make it a threat to fruit growers throughout the country. Organic control options are limited, but this article documents current research efforts and outlines various ways that growers can limit SWD presence and infestation on their land. This includes choosing crops whose fruiting phenology does not match up with SWD presence in their area, wise use of organically-approved sprays and attract-and-kill devices, employing plastic or fabric mulch to inhibit the development of infested fruit that has fallen on the canopy floor, and using exclusion tunnels to create a physical barrier between the crops and SWD in the field. Even more innovative research is being conducted on organic SWD control, so check the Organic Management of Spotted Wing Drosophila website for updates!

References and Citations
  • Asplen, M. K., G. Anfora, A. Biondi, D.-S. Choi, D. Chu, K. M. Daane, …N. Desneux. 2015. Invasion biology of spotted wing Drosophila (Drosophila suzukii): A global perspective and future priorities. Journal of Pest Science 88:469–494. Available online at: https://doi.org/10.1007/s10340-015-0681-z (verified 16 Nov 2017).
  • Cormier, D., J. Veilleux, A. Firlej. 2015. Exclusion net to control spotted wing Drosophila in blueberry fields. IOBC-WPRS Bulletin 109:181–184. Available online at: https://www.researchgate.net/profile/Annabelle_Firlej/publication/273458102_Exclusion_net_to_control_spotted_wing_Drosophila_in_blueberry_fields/links/5503304c0cf24cee39fd635f.pdf) (verified 15 Nov 2017).
  • Goodhue, R. E., M. Bolda, D. Farnsworth, J. C. Williams, and F. G. Zalom. 2011. Spotted wing drosophila infestation of California strawberries and raspberries: Economic analysis of potential revenue losses and control costs. Pest Management Science 67:1396–1402. Available online at: http://onlinelibrary.wiley.com/doi/10.1002/ps.2259/abstract (verified 16 Nov 2017).
  • Hauser, M. 2011. A historic account of the invasion of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) in the continental United States, with remarks on their identification. Pest Management Science 67:1352–1357. Available online at: https://doi.org/10.1002/ps.2265) (verified 15 Nov 2017).
  • Kinjo, H., Y. Kunimi, and M. Nakai. 2014. Effects of temperature on the reproduction and development of Drosophila suzukii (Diptera: Drosophilidae). Applied Entomology and Zoology 49:297–304. Available online at: https://doi.org/10.1007/s13355-014-0249-z) (verified 15 Nov 2017).
  • Lee, J. C., D. J. Bruck, H. Curry, D. Edwards, D. R. Haviland, R. A. Van Steenwyk, and B. M. Yorgey. 2011. The susceptibility of small fruits and cherries to the spotted-wing drosophila, Drosophila suzukii. Pest Management Science 67:1358–1367. Available online at: https://doi.org/10.1002/ps.2225) (verified 15 Nov 2017).
  • Rice, K. B., B. D. Short, S. K. Jones, and T. C. Leskey. 2016. Behavioral responses of Drosophila suzukii (Diptera: Drosophilidae) to visual stimuli under laboratory, semifield, and field conditions. Environmental Entomology 45:1480–1488. Available online at: https://doi.org/10.1093/ee/nvw123) (verified 16 Nov 2017).
  • Rice, K. B., B. D. Short, and T. C. Leskey. 2017. Development of an attract-and-kill strategy for Drosophila suzukii (Diptera: Drosophilidae): Evaluation of attracticidal spheres under laboratory and field conditions. Journal of Economic Entomology 110:535–542. Available online at: https://doi.org/10.1093/jee/tow319) (verified 15 Nov 2017).
  • Rogers, M. A., E. C. Burkness, and W. D. Hutchison. 2016. Evaluation of high tunnels for management of Drosophila suzukii in fall-bearing red raspberries: Potential for reducing insecticide use. Journal of Pest Science 89:815–821. Available online at: http://dx.doi.org/10.1007/s10340-016-0731-1 (verified 16 Nov 2017).
  • Takamori, H., H. Watabe, Y. Fuyama, Y. Zhang, and T. Aotsuka. 2006. Drosophila subpulchrella, a new species of the Drosophila suzukii species subgroup from Japan and China (Diptera: Drosophilidae). Entomological Science 9:121–128. Available online at: https://doi.org/10.1111/j.1479-8298.2006.00159.x) (verified 15 Nov 2017).

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23509

Finding a Pasture Stick in Your Area for Your Organic Dairy Farm

jeu, 2017/10/26 - 13:56

eOrganic author:

Debra Heleba, University of Vermont Extension

In the video, "Calculating Dry Matter Intake in Organic Pastures Using a Pasture Stick," speaker Sarah Flack demonstrates how to measure dry matter available from pasture using or pasture or grazing stick.

Sources of Pasture Sticks by State

It is important to note that not all pasture sticks are exactly the same. Sticks from each state and/or region may vary based on different forage species, production, and growth stages  due to climate, elevation, and other factors. Most states and/or regions that have pasture sticks customize them to specifically address their growing conditions.

The following is a list of contacts where you may find a pasture stick in your state. If your state is not listed, try contacting your local USDA Natural Resources Conservation Serivce (NRCS) office, your local affiliate of the American Forage and Grassland Council (if your state has one), or the national Grazing Lands Conservation Initiative.

Manufacturers of Pasture Sticks

If you are a service provider and/or farmer interested in getting multiple pasture sticks made, the following is a partial list of stick manufactures provided by grazing specialists. Please note that these references are for informational purposes only, and no endorsement or approval is intended.

  • Apex Advertising, www.apexadv.com, Deb Shank, 717-464-8828
  • Corporate Gifts and Incentives, Cindi Green, 605-582-8102
  • High Sierra, Mike Johnson, 800-288-7989, 530-223-2981
  • SEMO Specialties, 573-243-0090

 

 


 

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 5429

Dung Beetles: How to Identify and Benefit from Nature’s Pooper Scoopers

mer, 2017/10/04 - 16:14

eOrganic authors:

Matthew S. Jones, Washington State University

William E. Snyder, Wasnington State University

Introduction

Many organic vegetable farmers apply composted manure to enhance soil fertility, and some include livestock in their farming operations. All farms are visited by birds, deer, or other wildlife—all of which represent routes for animal feces to come in contact with fresh produce. This poses a risk to food safety in the rare cases that these feces are contaminated with human pathogens such as harmful strains of Salmonella, Listeria, Campylobacter, or Escherichia coli (Behling, 2010; Rasmussen and Casey, 2001). In turn, outbreaks of foodborne pathogens endanger human health and bring financial and legal risks to growers (Beretti and Stuart, 2008).

Fortunately, nature has provided a poop removal crew that can quickly remove fresh feces before it has a chance to contaminate produce. These creatures can also speed the release of plant-available nutrients contained in animal manure. Key among these are the dung beetles (families Scarabaeidae and Geotrupidae), who specialize in consuming fresh feces as larvae and adults. These insects play an important role in manure processing by consuming, burying, and breaking up the waste that both livestock and wildlife may deposit on farms (Doube, 1990; Menéndez et al., 2016). Here we focus on the benefits of dung beetles to vegetable and pasture production, the beetles’ feeding behaviors, and how to recognize a few key species likely to be seen on West Coast farms. Additionally, we make suggestions for how farmers can conserve dung beetles to maximize the many benefits that they offer. 

Benefits of Dung Beetles

Dung beetles offer numerous benefits, including:

Suppression of human and livestock pathogens: By feeding on fresh feces and using it to provision their nests, dung beetles suppress dung-dwelling human and livestock parasites and pathogens (Nichols et al., 2008). Indeed, calves grazing on pasture with healthy dung beetle populations can have 75% fewer parasites (Fincher, 1975). Likewise, dung beetles can also kill pathogenic E. coli when they bury dung (Jones et al., 2015), making it less likely for these pathogens to contaminate produce. By eating both parasites and human pathogens, dung beetles can greatly improve human and livestock health. It should be noted that dung beetles feed on fresh feces, so pathogens found in improperly composted manure may be less likely to be consumed by dung beetles.

Improved soil hydrological properties: Many dung beetle species bury dung under the soil as food for their larvae (see Feeding Behavior below). This digging activity creates holes in the soil that increases permeability, aerating the soil (Bang et al., 2005) and allowing water to soak in instead of running off the surface (Brown et al., 2010).

Enhanced soil nutrient cycling: By burying freshly-deposited feces, dung beetles move nutrient-rich organic material to where plant roots can reach it and where it can feed other beneficial soil organisms (Bang et al., 2005; Manning et al., 2016). This also instigates micro-organismal and chemical changes in the upper soil layers, which accelerates ammonification, nitrification, denitrification, and nitrogen (N2) fixation (Yokoyama et al., 1991).

Reduced greenhouse gas emissions: By aerating and burying cattle dung pats on pasture, Slade et al. (2016) found that dung beetles could lower emission of the important greenhouse gas methane by up to 12%. Unfortunately, this same study found that conventional feedlots had few dung beetles, minimally reducing greenhouse gas by as little as 0.05%.

Reduced populations of pest flies: Some dung-breeding flies are pests of cattle, feeding on blood or around the cows’ eyes, mouth, and nostrils (Haufe, 1987). These pests retard cattle growth and are expensive to control (Byford et al., 1992). Fortunately, dung beetles can bury feces before fly eggs and larvae have a chance to develop (Bishop et al., 2005). This means that dung beetles are important natural controls of pest flies.

Feeding Behavior

Dung beetles have three different lifestyles: rollers (telecoprids), tunnelers (paracoprids), and dwellers (endocoprids) (Fig. 1). Rollers form the pat into balls that are rolled to a suitable site and buried. Tunnelers consume the dung pat and burrow into the soil beneath the pat. Manure dwellers consume the manure pat and deposit their eggs either in the same place or in the soil adjacent to the pat.

Figure 1. Cross section of a dung pat showing the three dung beetle nesting types: dwellers, tunnelers, or rollers. Photo Credit: Kevin Floate, Agriculture and Agri-food Canada, 2011.

Cantonon pilulanrius

Figure 2. The tumblebug (Canthon imitator) is a good example of a roller (telecoprid) species. Photo Credit: Whitney Cranshaw, Colorado State University, Bugwood.org.

Figure 3. Holes like this in cattle manure indicate dung beetle feeding. Photo Credit: Debra Murphy, realagriculture.com.

Management

Many of the same chemicals used to kill internal parasites of conventional livestock also harm or kill dung beetles (O'Hea et al., 2010; Beynon et al., 2012; Floate et al., 2005; Verdú et al., 2015). This means that producers trying to kill harmful livestock parasites with chemicals may also be accidentally killing beneficial dung beetles (Wall and Strong, 1987). While organic farmers are allowed to vaccinate livestock, the routine use of antibiotics, harmful to dung beetles, is prohibited. Eliminating these chemicals by farming organically is a great way to conserve dung beetles and maximize the benefits these beetles offer.

For organic farmers wanting to maximize the benefits of dung beetles, a few guidelines are:

  • Take care not to overgraze pastures, which may reduce vegetation cover and increase soil exposure, and has been shown to result in high soil loss and compaction (Negro et al., 2011). This may directly disturb dung beetles, modify their habitat, or influence microhabitat requirements for larval development of the different functional groups—especially telecoprids and paracoprids—which require specific soil characteristics for burying dung and building nests (Bertone et al., 2006; Negro et al., 2011).
  • If possible, maintain a diversity of ungulate species, which will increase dung beetle diversity and improve dung decomposition (Hutton and Giller, 2003).

For conventional farmers contemplating a transition to organic production and conventional farmers interested in reducing their impact on dung beetles, a few guidelines are:

  • Rotate stock around fields and allow fields to fallow three weeks between grazing of the same animal species to help break parasite cycles in fields without using chemicals.
  • Treat only livestock known to have parasites, rather than using preventative antibiotic treatments.
  • Use chemicals less toxic to dung beetles, especially when cattle are out on pasture. See Beynon (2016) for more guidance on how to do this.
  • Do not under-dose animals. Parasiticides are not effective unless the right dose is applied.
  • Do not move treated animals onto fresh pasture immediately after treatment, and always ensure there is some untreated dung for beetles to eat.
Identification of Common Species

Figure 4. Canthon simplex (LeConte, 1857), commonly known as a “Tumblebug,” is a roller (telecoprid) species that is 5-9mm long. This species is plain black and very smooth. Also look for the serrated edge on the front of its head (as seen in the photo). This species can be found during the spring and summer throughout most of the U.S. West Coast. More info can be found at: http://www.americaninsects.net/b/canthon-simplex.html. Photo Credit: Gary Griswold, bugguide.net.

Figure 5. Onthophagus taurus (Schreber 1759), commonly known as the “Bull Headed Dung Beetle,” is a tunneler (paracoprid) species that is 6.0-11.5mm long. This species is all black, sometimes with a greenish sheen. Males often have a pair of long horns sweeping back off their head (like a bull). This species can be found from spring through autumn throughout the United States. More information about this species can be found at: http://bugguide.net/node/view/23972. Photo Credit: Frank Guarnieri, bugguide.net.

Figure 6. Onthophagus nuchicornis (Linnaeus 1758) is a tunneler (paracoprid) species that is 6-8mm long. This species has a gold back speckled with black dots. Males often have a single spine-like horn and females have a ridge across the base of their head. This species can be found from early spring until late autumn from southern Oregon (United States) to Canada, as well as in northern latitudes across the United States. More information can be found at: http://bugguide.net/node/view/29475. Photo Credit: Emmy Engasser, Hawaiian Scarab ID, USDA APHIS ITP, Bugwood.org.

Figure 7. Aphodius fimetarius (Linnaeus, 1758) is a dweller (endocoprid) species that is 5-8mm in length. This species has ribbed, bright orange-red outer wings with a black head and thorax. This species is most likely to be found in the spring and autumn throughout the United States. More information can be found at: http://www.thewcg.org.uk/scarabaeidae/0003G.htm. Photo Credit: Emmy Engasser, Hawaiian Scarab ID, USDA APHIS ITP, Bugwood.org.

Additional Resources

Team Scarab at the University of Nebraska State Museum is the absolute taxonomic guru for help identifying obscure and interesting dung beetles. They maintain a large portion of the Smithsonian Museum’s dung beetle collection and can be found at: http://museum.unl.edu/research/entomology/index.htm.

Information regarding other (non-dung-feeding) beneficial beetles can be found at: http://ento.psu.edu/extension/factsheets/ground-beetles.

References and Citations 
  • Arnett, R. H., M. C. Thomas, P. E. Skelley, and J. H. Frank (eds.). 2002. American beetles. Volume 2: Polyphaga: Scarabaeoidea through Curculionoidea. CRC Press, Boca Raton, FL.
  • Bang H. S., J-H. Lee, O. S. Kwon, Y. E. Na, Y. S. Janga, and W. H. Kim. 2005. Effects of paracoprid dung beetles (Coleoptera: Scarabaeidae) on the growth of pasture herbage and on the underlying soil. Applied Soil Ecology 29: 165—171. (Available online at: https://doi.org/10.1016/j.apsoil.2004.11.001 (verified 2 Oct 2017).
  • Behling, R. G., J. Eifert, M. C. Erickson, J. B. Gurtler, J. L. Kornacki, E. Line, R. Radcliff, E. T. Ryser, B. Stawick, and Z. Yan. 2010. Selected pathogens of concern to industrial food processors: Infectious, toxigenic, toxico-infectious, selected emerging pathogenic bacteria. p. 5—61. In J. L. Kornacki (ed.) Principles of microbiological troubleshooting in the industrial food processing environment in food microbiology and food safety. Springer-Verlag New York.
  • Beretti, M., and D. Stuart. 2008. Food safety and environmental quality impose conflicting demands on Central Coast growers. California Agriculture 62: 68–73. (Available online at: http://ucanr.edu/repository/fileaccess.cfm?article=65599&p=ZBCUWA&CFID=516610733&CFTOKEN=57164707 (verified 2 Oct 2017).
  • Bertone, M., W. Watson, M. Stringham, J. Green, S. Washburn, M. Poore, and M. Hucks. 2006. Dung beetles of central and eastern North Carolina cattle pastures. (Available online at: http://www.ces.ncsu.edu/depts/ent/notes/forage/guidetoncdungbeetles.pdf (verified 2 Oct 2017).
  • Beynon, S. A., D. J. Mann, E. M. Slade, and O. Lewis. 2012. Species-rich dung beetle communities buffer ecosystem services in perturbed agroecosystems. Journal of Applied Ecology 49: 1365–1372. (Available online at: https://doi.org/10.1111/j.1365-2664.2012.02210.x (verified 3 Oct 2017).
  • Beynon, S. A. 2016. Fact sheet 2: Sustainable use of wormers and other parasiticides for cattle, sheep, and horses [Online]. Dung Beetles Direct. Available at: http://www.drbeynonsbugfarm.com/CMSDocuments//Fact%20sheet%202_Parasiticides_Aug%202016.pdf (verified 19 July 2017).
  • Bishop, A. L., H. J. McKenzie, L. J. Spohr, and I. M. Barchia. 2005. Interactions between dung beetles (Coleoptera: Scarabaeidae)and the arbovirus vector Culicoides brevitarsis Kieffer (Diptera:Ceratopogonidae). Australian Journal of Entomology 44: 89–96. Available online at: https://doi.org/10.1111/j.1440-6055.2005.00455.x (verified 2 Oct 2017).
  • Brown, J., C. H. Scholtz , J.-L. Janeau, S. Grellier, and P. Podwojewski. 2010. Dung beetles (Coleoptera: Scarabaeidae) can improve soil hydrological properties. Applied Soil Ecology 46: 9–16. (Available online at: https://doi.org/10.1016/j.apsoil.2010.05.010 (verified 2 Oct 2017).
  • Byford, R. L., M. E. Craig, and B. L. Crosby. 1992. A review of ectoparasites and their effect on cattle production. Journal of Animal Science 70: 597–602. (Available onlne at: https://doi.org/10.2527/1992.702597x (verified 3 Oct 2017).
  • Doube, B. M. 1990. A functional classification for analysis of the structure of dung beetle assemblages. Ecological Entomology 15: 371–383. (Available online at: https://doi.org/10.1111/j.1365-2311.1990.tb00820.x (verified 3 Oct 2017).
  • Eaton, E. R., and K. Kaufman. 2007. Kaufman Field Guide to Insects of North America. Houghton Mifflin Company, Boston, MA.
  • Fincher, G. T. 1975. Effects of dung beetle activity on number of nematode parasites acquired by grazing cattle. Journal of Parasitology 61: 759–762. (Available online at: https://doi.org/10.2307/3279480 (verified 3 Oct 2017).
  • Floate, K. D. 2011. Arthropods in cattle dung on Canada's grasslands. p. 71—88. In K. D. Floate (ed.) Arthropods of Canadian grasslands (Volume 2): Inhabitants of a changing landscape. Biological Survey of Canada. (Available online at: http://biologicalsurvey.ca/monographs/read/17 (verified 3 Oct 2017).
  • Floate, K. D., K. G. Wardhaugh, A.B.A. Boxall, and T. N. Sherratt. 2005. Fecal residues of veterinary parasiticides: Nontarget effects in the pasture environment. Annual Review of Entomology 50: 153–79. (Available online at: https://doi.org/10.1146/annurev.ento.50.071803.130341 (verified 3 Oct 2017).
  • Haufe, W. O. 1987. Host–parasite interaction of blood feeding dipterans in health and productivity of mammals. International Journal of Parasitology 17: 607–614. (Available online at: https://doi.org/10.1016/0020-7519(87)90137-8 (verified 3 Oct 2017).
  • Hutton, S. A., and P. S. Giller. 2003. The effects of the intensification of agriculture on northern temperate dung beetle communities. Journal of Applied Ecology 40:994–1007. (Available online at: https://doi.org/10.1111/j.1365-2664.2003.00863.x (verified 3 Oct 2017)
  • Jones, M. S., S. Tadepalli, D. F. Bridges, V.C.H. Wu, and F. A. Drummond. 2015. Suppression of Escherichia coli O157:H7 by dung beetles (Coleoptera: Scarabaeidae) using the lowbush blueberry agroecosystem as a model system. PLoS ONE 10: e0120904. (Available online at:
  • Manning, P., E. M. Slade, S. A. Beynon, and O. T. Lewis. 2016. Functionally rich dung beetle assemblages are required to provide multiple ecosystem services. Agriculture, Ecosystems & Environment: 218: 87–94. (Available online at: https://doi.org/10.1016/j.agee.2015.11.007 (verified 3 Oct 2017).
  • Menéndez, R., P. Webb, and K. H. Orwin. 2016. Complementarity of dung beetle species with different functional behaviours influence dung–soil carbon cycling. Soil Biology and Biochemistry 92: 142–148. (Available online at: https://doi.org/10.1016/j.soilbio.2015.10.004 (verified 3 Oct 2017).
  • Negro, M., A. Rolando, and C. Palestrini. 2011. The impact of overgrazing on dung beetle diversity in the Italian Maritime Alps. Environmental Entomology 40: 1081–1092. (Available online at: https://doi.org/10.1603/EN11105 (verified 3 Oct 2017).
  • Nichols, E., S. Spector, J. Louzada, T. Larsen, S. Amezquita, and M. E. Favila. 2008. Ecological functions and ecosystem services provided by Scarabaeinae dung beetles. Biological Conservation 141: 1461–1474. (Available online at: https://doi.org/10.1016/j.biocon.2008.04.011 (verified 3 Oct 2017).
  • O'Hea, N. M., L. Kirwan, P. S. Giller, and J. A. Finn. 2010. Lethal and sublethal effects of ivermectin on north temperate dung beetles, Aphodius ater and Aphodius rufipes (Coleoptera: Scarabaeidae). Insect Conservation and Diversity 3: 24–33. (Available online at: https://doi.org/10.1111/j.1752-4598.2009.00068.x (verified 3 Oct 2017).
  • Rasmussen, M. A. and T. A. Casey. 2001. Environmental and food safety aspects of Escherichia coli O157:H7 infections in cattle. Critical Reviews in Microbiology 27:57–73. (Available online at: http://dx.doi.org/10.1080/20014091096701 (verified 3 Oct 2017).
  • Slade, E. M., T. Riutta, T. Roslin, and H. L. Tuomisto. 2016. The role of dung beetles in reducing greenhouse gas emissions from cattle farming. Scientific Reports 6: 18140. (Available online at: 10.1038/srep18140 (verified 3 Oct 2017).
  • Verdú, J. R., V. Cortez, A. J. Ortiz, E. González-Rodríguez, J. Martinez-Pinna, J.-P. Lumaret. 2015. Low doses of ivermectin cause sensory and locomotor disorders in dung beetles. Scientific Reports 5: 13912. (Available online at: https://doi.org/10.1038/srep13912 (verified 3 Oct 2017).
  • Wall, R. and L. Strong. 1987. Environmental consequences of treating cattle with the antiparasitic drug ivermectin. Nature 327: 418–421. (Available online at: https://doi.org/10.1038/327418a0 (verified 3 Oct 2017).
  • Yokoyama, K., K. Hideaki, and T. Hirofumi. 1991. Paracoprid dung beetles and gaseous loss of nitrogen from cow dung. Soil Biology and Biochemistry 23: 643–647. (Available online at: https://doi.org/10.1016/0038-0717(91)90077-W (verified 3 Oct 2017).

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23262

Live Broadcast: Organic Soil Health Research Special Session at the Tri-Societies Conference

lun, 2017/10/02 - 16:08

eOrganic is partnering with the Organic Farming Research Foundation to bring you a live online broadcast of the Special Session on Organic Soil Health Research at the Tri-Societies (ASA, CSSA and SSSA) Annual Meeting on October 25, 2017. The session lasts 2.5 hours, and takes place on Wednesday, October 25, 2017: 9:30 AM-11:35 AM Eastern Time (830AM Central, 730AM Mountain, 630AM Pacific Time).

The session will also be recorded and archived at eXtension.org and on the eOrganic YouTube channel. The online broadcast is free and open to the public, and advance registration is required. Because this takes place at an in-person conference, the exact program, speakers and start times may be subject to change! 

Register for the online broadcast at: https://attendee.gotowebinar.com/register/3992871364361428227

Organic Soil Health Research Symposium Program

Interest in and research results related to understanding soil health and management has been identified by researchers and farmers as the highest priority by the OFRF and other surveys conducted in the last two years. (National Organic Research Agenda, 2016) Soil erosion costs $400 billion/year globally and decreases productivity by $37.6 billion/year in the U.S. Excessive tillage and use of synthetic materials can destroy soil structure and interfere with microbial and root exudates. Nutrient retention and soil carbon improves soil organic matter and plant growth. There is a critical need to improve soil health in all agricultural systems and at a minimum maintain and decrease soil loss and increase ecosystem services provided by healthy soils. This symposium will bring together researchers, extension, farmers and other organic agriculture stakeholders to provide current information on applicable research results. Nine issues have been identified ranging from effects of cover corps, compost and rotation, insect and disease management interactions with soil biology, urban environments, to influence of soil management practices on economic returns and best ways to disseminate information to producers. Research results are applicable to organic and conventional production systems to improve sustainability and profit. This Special Session is being organized by Diana Jerkins of the OFRF, and will be presented in conjunction with co-sponsors Organic Management Systems Community and Soil Health Community, and co-project leaders, Danielle Treadwell, University of Florida and Marty Mesh, Florida Organic Growers.

930AM (Note: all times listed here are Eastern Time)
Introductory Remarks

9:35 AM
Setting and Exceeding Benchmarks for Soil Health on Diversified Organic Vegetable Farms. Abstract
John Franklin Egan, Pennsylvania Association for Sustainable Agriculture; Helen Kollar-McArthur, Pennsylvania Association for Sustainable Agriculture; Dan Dalton, Pennsylvania Association for Sustainable Agriculture; Kristy Borrelli, The Pennsylvania State University; Charlie White, Pennsylvania State University

9:50 AM
Comparison of Reduced Tillage Practices for Small-Scale Organic Vegetable Production. Abstract
Ryan Maher, Cornell University; Anu Rangarajan, Cornell University; Mark Hutton, University of Maine Cooperative Extension; Brian Caldwell, Cornell University; Mark L. Hutchinson, University of Maine Cooperative Extension; Nicholas Rowley, University of Maine Cooperative Extension

10:05 AM
Using Mycorrhizal Fungi to Improve Soil Health and Increase Yield in Organic Vegetable Farms. Abstract
Pushpa Soti, University of Texas Rio Grande Valley; Alexis Racelis, University of Texas Rio Grande Valley

10:20 AM
Effects of Soil Balancing Treatments on Soils, Crops and Pests in Organically Managed Farms. Abstract
Andrea Leiva Soto, The Ohio State University; Steve Culman, Ohio State University; Warren A Dick, Ohio State University; Matthew Kleinhenz, The Ohio State University; Catherine Herms, The Ohio State University; Douglas Doohan, The Ohio State University

10:35 AM
Organic Agriculture's Ongoing Contribution to Soil Health and the Oeconomy. Abstract
Michelle Wander, University of Illinois-Urbana-Champaign

10:50 AM
Optimizing Nitrogen Management on Organic and Biologically-Intensive Farms. Abstract
Douglas P. Collins, Washington State University; Andy Bary, Washington State University

11:05 AM
Soil Health and Organic: Lessons Learned. Abstract
Ben Bowell, Oregon Tilth; Jennifer Kucera, USDA-NRCS

11:20 AM
Influence of Long-Term Organic Cropping Systems on Soil Microbial Population Size and Structure. Abstract
Lea Vereecke, UW Madison; Erin Silva, University of Wisconsin-Madison; Josephine Peigne, ISARA-Lyon

11:35 AM
Adjourn

If you would like to attend the Tri-Societies Annual Meeting in person, find out more and register here.

Funding for this live broadcast is provided by USDA NIFA OREI.

System Requirements

View detailed system requirements here. Please connect to the webinar 10 minutes in advance, as the webinar program will require you to download software. To test your connection in advance, go here. You can either listen via your computer speakers or call in by phone (toll call). Java needs to be installed and working on your computer to join the webinar. If you are running Mac OSU with Safari, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar, and if it isn't working, try Firefox or Chrome.

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23624

Abrasive Weeding: A New Tool for Weed Management in Organic Agriculture

mer, 2017/09/06 - 13:24

eOrganic authors:

Sam Wortman, University of Nebraska Lincoln

Frank Forcella, USDA-ARS

Sharon Clay, South Dakota State University

Daniel Humburg, South Dakota State University

Introduction

Abrasive weeding is a non-chemical weed management tool. Weed leaves and stems are abraded by small grits propelled by compressed air. This abrasion results in defoliation, stem breakage, or tissue damage leading to weed injury or, ideally, mortality. Early research on abrasive weeding began with greenhouse studies to demonstrate that small weeds could be killed with air-propelled grits. More recent research has focused on the development of grit-applicator machines and specialized nozzles, and the potential for using organic fertilizers as grits to integrate weed and nitrogen management in one field pass. Abrasive weeding is similar to flame weeding in that both are non-chemical, zero-tillage tactics for post-emergence weed control in certified organic agriculture. However, abrasive weeding is likely safer, less energy-intensive, and less damaging to crop yield when used to control in-row weeds. In addition, abrasive grit applicators can double as precision nutrient delivery tools. This fact sheet highlights the current state of abrasive weeding research and practice, including a summary of crops tested, applicator design considerations, expected weed control, possible grits, and economic feasibility.

Crops
  • Corn and soybean plants can be sprayed as early as the V1 growth stage without any reduction in crop yield (Erazo-Barradas, 2017).
  • Tomato and pepper plugs can be sprayed one week after transplanting. Stem abrasion is visible, but grit application does not reduce growth rate or yield (Wortman 2014, 2015).
  • Small fruit liner plants (raspberry, for example) can be sprayed immediately after transplanting. As the weed community shifts from annual to perennial species during the establishment phase, abrasive weeding will become less effective.
  • Additional research in broccoli, sweet potato, edamame, snap bean, and hops is ongoing. Most crops with an upright stem architecture seem to be compatible with abrasive weeding.
Applicators

Grit applicators consist of three basic parts: 1) air compressor, 2) grit hopper and meter, and 3) nozzle and tubing.

  • Air compressors: Reciprocating air compressors (available at hardware stores; suggest >5 HP engine, 155 psi max pressure, >5 CFM @ 90 psi) are suitable for single-nozzle, hand-held grit application, but a rotary-screw air compressor is required for continuous application of grits within a crop row with multiple nozzles.
  • Hopper and meter: For grit applicators available at a hardware store, grit is either siphoned from the hopper or delivered via pressure or gravity. Unfortunately, these systems are susceptible to clogging when irregularly-shaped organic materials are used as grits. Our team developed a motor-driven grit meter to prevent clogging and provide more precise control of application delivery rate.
  • Nozzles and tubing: Nozzles available at a hardware store can be effective, but grits can often clog the small orifice that accelerates air, so our team developed a special nozzle to prevent clogging by bypassing this orifice. Each nozzle requires two different tubes: one carrying compressed air and the other carrying grit.

The grit meter and nozzle developed by our team are not yet commercially available. However, if you are interested in purchasing a custom meter or nozzle for agricultural grit application, please contact Sam Wortman (swortman@unl.edu).

Grit applicators have been developed for different production scales and cropping systems, ranging from 1 (bottom) to 8 nozzles (top left). Photo credits: Frank Forcella, USDA ARS: top left and bottom right; Sam Wortman, UNL: top right and bottom left.

Potential Weed Suppression

Research suggests that two applications of grit, approximately 10 and 24 days after seeding or transplanting, can reduce weed biomass in the treated area by 50% to 95%. However, actual weed suppression depends on weed community composition (annual broadleaves are more susceptible than grasses and perennials) and abundance, weed growth stage (small weeds with fewer than three true leaves are most susceptible), environmental conditions (rainfall events stimulate additional weed germination), and cropping system (a dense crop canopy may reduce weed regrowth after grit application). Weed suppression is also a product of how long a weed is exposed to abrasive grit; driving or walking slowly (<1 mph) can improve efficacy.

Table 1. Weed control (%) after two grit applications, measured as a reduction in weed biomass relative to a weedy check in grain and vegetable cropping systems.

Potential Grit Sources

Any OMRI-listed material (check with your certifier) can be used as an abrasive grit if it can be ground or milled to a mesh size between 40 and 20 (0.015 – 0.035 inch diameter). Excessively fine or lightweight grits should not be used as they increase the chance of clogging the applicator nozzle and create a dust inhalation hazard. For example, greensand and rock phosphate organic fertilizers should not be used due to excessive dust.

Table 2. Advantages and disadvantages observed for different sources of abrasive grit.

Profitability

The cost of abrasive weeding is similar to that of hand-weeding, but it can reduce labor needs four-fold. The largest expenses of abrasive weeding are the applicator and grits. We estimate that the cost of materials for the eight-, two-, and single-nozzle applicators is $10,500, $7,100, and $1,200, respectively, and the cost of most grits ranges from $0.10 to $0.80 per pound. Thus, profitability increases with the number of acres farmed and when the cost of grits is low (which requires grits be purchased by the ton or produced inexpensively on-farm). Organic fertilizers as grits may increase profitability by reducing nitrogen input costs. Overall, abrasive weeding is most economical in high-value specialty crops where manual hand-weeding costs are typically high and potential revenue loss from weed competition justifies an intensive, weed-free management approach.

Weed growth 1 month after final grit application to the planting hole area in tomato. Left: No grit application. Right: Two applications of walnut shell grits. Photo credit: Sam Wortman, UNL.

Funding for this project was provided in part by USDA NIFA OREI award # 2014-51300-22233

References and Citations
  • Erazo-Barradas, M., C. N. Friedrichsen, F. Forcella, D. Humburg, and S. A. Clay. 2017. Propelled abrasive grit applications for weed management in transitional corn grain production [Online]. Renewable Agriculture and Food Systems. Available at: https://doi.org/10.1017/S174217051700031X (verified 4 Sep 2017)
  • Wortman, S. E. 2014. Integrating weed and vegetable crop management with multifunctional air-propelled abrasive grits. Weed Technology 28(1):243–252. Available online at: https://doi.org/10.1614/WT-D-13-00105.1 (verified 4 Sep 2017)
  • Wortman, S. E. 2015. Air-propelled abrasive grits reduce weed abundance and increase yields in organic vegetable production. Crop Protection 77:157–162. Available online at: https://doi.org/10.1016/j.cropro.2015.08.001 (verified 4 Sep 2017)
     

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23223

January 2017

lun, 2017/07/24 - 11:59
New eOrganic Webinars

We're excited to bring you a new season of webinars on organic farming and research! Registration is open for our spring 2017 webinar series, and we hope you can join us for as many as possible! Click on the links to find out more about them and register.

  • February 1, 2017: Management of Spotted Wing Drosophila Using Organic Strategies
    • Members of a multi-state research project will provide a comprehensive update on organic management of spotted wing drosophila. It will cover findings of the research conducted during the first year of this project on organically approved strategies including: 1) behavioral strategies to improve monitoring (using more attractive baits and lures) and management (attract and kill approach); 2) cultural strategies to lower SWD populations in the field (canopy and floor management, and using exclusion netting); and 3) chemical strategies (using organically approved insecticides in combination with adjuvants and phagostimulants. Presenters are Ash Sial, UGA; Mary Rogers, UMN; Christelle Guedot, UWisc; Kelly Hamby, UMD;Rufus Isaacs, MSU; Tracy Leskey, USDA; Vaughn Walton, OSU.
       
  • February 7, 2017: Providing Habitat for Wild Bees on Organic Farms
    • This webinar will look at habitat augmentation techniques useful for both wild bee conservation and the promotion of pollination services, with special attention to native plant selection and installation, experimental ground nest preparation, and cavity-nest construction. Presenters are Elias Bloom and Rachel Olsson, Washington State University; Bridget McNassar, Oxbow Farm.
       
  • February 15, 2017: Integrated Clubroot Management for Brassica Crops
    • In this webinar we will explore the life-cycle of clubroot, environmental factors influence disease incidence and severity, prevention measures to minimize between field and in-field spread, and management strategies to reduce crop damage. Particular attention will be focused on soil pH management using lime. Presenters are Aaron Heinrich and Alex Stone, OSU.
       
  • March 7, 2017: Tomato Varietal Improvement
    • Participants will describe how to develop and select improved vegetable varieties using the breeding component of the Tomato Organic Management and Improvement (TOMI) project as an example. The goal of this project is to develop new tomato varieties that are resistant to the most problematic diseases facing organic tomato growers, and have the good fruit flavor that customers expect from heirloom varieties. Presenters are Julie Dawson, University of Wisconsin; Lori Hoagland and Dan Egel, Purdue; James Myers and Kara Young, Oregon State, Laurie McKenzie, Jared Zystro, Organic Seed Alliance.
       
  • March 30, 2017: Using Biofungicides, Biostimulants and Biofertilizers to Boost Crop Productivity and help Manage Vegetable Diseases
    • In this webinar, participants will describe the different types of products available in the marketplace today, provide an overview of recent studies evaluating their efficacy, and discuss strategies for identifying the most effective products and application practices. Presenters are Giuseppe Colla, Tuscia University, MariaTeresa Cardarelli, Italian Ministry of Agriculture, Dan Egel, Laurie Hoagland, Purdue University.
       
  • April 11, 2017: Use of High Glucosinolate Mustard as an Organic Biofumigant in Vegetable Crops
    • In this webinar, we’ll address the use of mustard cover crops that have been bred specifically to have high glucosinolate concentrations and act as a biofumigant in crops like potatoes, peppers, black beans, and strawberries. Presenters are Heather Darby and Abha Gupta, University of Vermont Extension; and Katie Campbell-Nelson, University of Massachusetts,
Recent Cucurbit Webinars

We recently ran a series of 3 cucurbit webinars from the Eastern Sustainable Organic Cucurbit Project-on viruses, downy mildew, and striped cucumber beetles. We recorded them all, and the first 2 are already in our archive--the third one will be available within the coming week! Find them all in our archive and on the eOrganic YouTube channel:

For additional information about cucumber beetles, read the eOrganic article on Managing Cucumber Beetles in Organic Farming by William Snyder of Washington State University.

Pollination Webinars from the Bee Health Community on eXtension

Meanwhile, our friends at the eXtension Bee Health Community of Practice have been busy organizing a webinar series on pollination. Applicable to both organic and conventional farmers, these webinars will provide an overview of pollination requirements and strategies to ensure the pollination of specialty crops. Farmers and gardeners rely on crop pollinators, including honey bees, alternative managed bees like the blue orchard bee, and wild bees. Pollination experts will discuss how to support these pollinators in almond, blueberry, tree fruit, pumpkin, and watermelon.

Find out more about the series and register at http://articles.extension.org/pages/74051 and read a flyer here

Spotted Wing Drosophila Research Update

Over the past year we've been including updates in this newsletter on an important multi-state research project on Spotted Wing Drosophila. Some of the many team members are presenting a webinar on February 1st, see above, but they have also been posting updates on their research at different locations around the country. This month, read about their experiments on SWD exclusion with netting and tunnels in Minnesota on fall-bearing raspberries, and in Arkansas on blackberries. Be sure to attend the upcoming webinar on SWD to hear more about this project! Find the project website with additional information at http://eorganic.info/node/12848.

In Good Tilth Winter Issue and Organicology

In Good Tilth Winter 2017issue has been published and the theme is Transition.This issue features a few different research projects on the topic, including the Tools for Transition project out of MN and the Organic Hotspots research from Penn State (and OTA) feature article on our partnership w/ OSU, with a section highlighting eOrganic.

Also, Tilth's biennial conference Organicology is coming up Feb. 2-4 in Portland, OR. The event draws about 1000 attendees over 3 days for keynotes, intensives, workshops, a trade show and celebration. Early registration rates end on January 20, so don’t delay signing up. eOrganic will have a table at the conference, so we hope to see you there!

OGRAIN workshop on Jan 21-22

Registration is now open for the 2017 Organic Grain Production and Marketing Seminar at the University of Wisconsin Madison. Two days of expert presentations, engaging panels, productive discussions, and plenty of time to meet other farmers interested in organic grain production in the Upper Midwest. Come get the tools, techniques, and network necessary to get started and succeed in producing and marketing organic grains.

  • Doing the numbers on transition with Paul Dietmann of Badgerland Financial
  • Organic weed management with Gary McDonald, cultivation expert
  • Organic certification with Jackie DeMinter of MOSA
  • Organic grain 101 with Carmen Fernholz, A-Frame Farm and University of MN
  • Beginning farmer panel
  • Organic grain marketing panel
  • Food-grade grain production with Dr. Julie Dawson (UW-Madison) and Gilbert Williams (Lonesome Stone Milling LLC)
  • Organic No-Till production with Dr. Erin Silva and a farmer panel
  • Finding the right rotation for you (workshop led by successful organic grain farmers)
  • And many more....

Register here: http://ograin.bpt.me/

More upcoming organic conferences--this is by no means a complete list!

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 21750

May 2017

lun, 2017/07/24 - 11:57
Upcoming Events

The Organic Confluences Summit: Making Research Count, organized by the Organic Center, is just around the corner on May 22-23, 2017. The conference, which will be held in Washington, DC, features speakers including farmers, policy makers, industry members, researchers, certifiers and more as they explore case studies of current and past research and communication pathways. They will also hold participant conversations to identify challenges and recommendations for research needs identification, research project design development, and results dissemination. Registration is still open here.

Market News Organic Reporting Webinar: The USDA’s Agricultural Marketing Service (AMS) invites you to a live, interactive webinar on Organic Reporting within multiple Market News divisions. Join them to learn about how the Specialty Crops, Dairy, Livestock, Poultry & Seed, and Cotton & Tobacco Market News programs provide you with free access to market information about organic products. The webinar  takes place on Thursday, May 18, 2017 at 2PM Eastern Time, and it will cover areas such as:

  • The scope of AMS’s Organic reporting capabilities
  • Our new Organic's landing page
  • The easy to use AMS Market News Portal for timely, accurate information
  • Highlighting the Organic Grain & Feedstuff report
  • How you can put Market News Organic reports to work for your business

Presenters are Kimberly Mercer, Assistant to the Director, Specialty Crops Market News Division; Eric Graf Senior Market News Reporter of the Dairy Program Market News Division; and Russell Avalos, Market News Reporter for the the Livestock, Poultry, and Grain Market News Division. Register here.

Oregon Tilth Webinar Series: Oregon Tilth is running a  webinar series this year in partnership with the NRCS. Upcoming topics in June include the results of an organic transition survey, Bee Better certification, and  innovative cover cropping techniques. Check out the entire series and register for the webinars here.

Comments Sought on the Organic Livestock and Poultry Rule

On January 19, 2017, the USDA published the final rule on animal welfare standards for organic livestock and poultry in the Federal Register. According to a press release, the rule would ensure consistent application of the USDA organic regulations for organic livestock and poultry operations and maintain confidence in organically labeled products. Based on recommendations from the National Organic Standards Board and stakeholder suggestions, the final rule:

  • Establishes minimum indoor and outdoor space requirements for poultry
  • Clarifies how producers and handlers must treat livestock and chickens for their health and welfare
  • Specifies which physical alterations are allowed and prohibited in organic livestock and poultry production.

Implementation of the rule has been delayed until November, 14th 2017, and the USDA recently announced that it is asking for comments on whether to implement the rule on the planned date, suspend the rule indefinitely and possibly change or withdraw it, delay the implementation further, or withdraw it altogether. Comments are being accepted until June 9, 2017 here.

Organic Farming Shows Continued Growth

Last month the USDA announced new data showing that the organic industry continues to grow domestically and globally, with 24,650 certified organic operations in the United States, and 37,032 around the world. The 2016 count of U.S. certified organic farms and businesses reflects a 13 percent increase between the end of 2015 and 2016, continuing the trend of double digit growth in the organic sector. The number of certified operations has increased since the count began in 2002 and this is the highest growth rate since 2008. Find out more here.

Also, to be counted in this year's Census of Agriculture, you can sign up to receive a mailed form until the end of June, 2017 at this link, where you can also fill it out electronically by scrolling down and clicking on the yellow button that says "Make Sure You Are Counted". This census is done every 5 years, and the National Agriculture Statistics service considers farms to be places where $1,000 or more of fruits, vegetables and some animals are raised and sold, or normally would have been sold, during the Census year.

eOrganic Mission

eOrganic is a web community where organic agriculture farmers, researchers, and educators network; exchange objective, research- and experience-based information; learn together; and communicate regionally, nationally, and internationally. If you have expertise in organic agriculture and would like to develop U.S. certified organic agriculture information, join us at http://eorganic.info.

eOrganic Resources

Find all eOrganic articles, videos and webinars at http://extension.org/organic_production

Connect with eOrganic on Facebook and Twitter, and subscribe to our YouTube channel!

Have a question about organic farming? Use the eXtension Ask an Expert service to connect with the eOrganic community!

eOrganic logo

 

 

 

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 22710

June 2017

lun, 2017/07/24 - 11:57
New eOrganic Video on Ancient Grains: Emmer, Einkorn and Spelt

Learn about growing and dehulling the "ancient" grains emmer, einkorn and spelt in this new video created by members of the NIFA OREI funded research project Value Added Grains for Local and Regional Food Systems. Learn about planting rates and nutrient requirements, as well as seeding and dehulling equipment. Watch the video here, and check out additional archived webinars about ancient grains on the eOrganic YouTube channel.

New Spotted Wing Drosophila Publications

New publications on the organic management of Spotted Wing Drosophila are available from a multi-state NIFA OREI research project that is researching ways to control this invasive pest. Many of these publications are open-access, so you can read them in full without a journal subscription. Learn about using high tunnels and exclusion netting to reduce SWD in raspberries,  the effect of non-nutritive sugars, the effect of border sprays and between-row tillage, and more here. Find the publications at https://eorganic.info/spottedwingorganic/resources.

New Soil Health, Weed Management and Conservation Tillage Guides

The Organic Farming Research Foundation offers three new and informative guides on soil health, weed management  and conservation tillage in organic farming systems. Topics covered include how to enhance soil organic matter, weed management tools that reduce the need for soil disturbance, and soil-friendly tillage practices. They also include reviews of USDA funded organic research, future research priorities, and scientific literature references. All three guides will download free of charge at this link, and additional guides on cover crops, plant breeding, water management and quality, and nutrient management will be available soon.

Farm Volunteers and Interns Guide

A new guide--published by Farm Commons, a non-profit that provides farmers and the agricultural community with legal education—provides insights and strategies to help farmers reduce liability risks related to interns and volunteers. “Managing the Risks of Interns and Volunteers,” is available for free download on the Farm Commons website at: https://farmcommons.org/resources-search. You will need to create an account first in order to download the guide. The Farm Commons site also has state-specific guides for Pennsylvania, Vermont, and New Hampshire that discuss intern and volunteer issues specific to those states.

Organic Seed Trials and Selection Webinar

The second webinar in this year's Organic Seed Production Webinar Series will take place on June 16th. This webinar will cover the basics of conducting on-farm variety trials including sourcing germplasm, field plot design, trial evaluation, and making sense of the data. Presenters will also cover basics of field selection or roguing to improve performance of open pollinated seed crops. Register once for this free webinar and you can attend any or all of the webinars in the series which take place once a month through October. The series is organized by the Organic Seed Alliance and the Multinational Exchange for Sustainable Agriculture. Register here.

New SARE Toolkit Helps Plan On-Farm Field Days

‘Tis the season for on-farm field days, demonstrations, and other farm events. To help researchers, educators, and farmers alike plan and conduct on-farm events, the Sustainable Agriculture Research and Education Program (SARE) has developed a new publication, the Farmer Field Day Toolkit. The Toolkit is an online, comprehensive resource of step-by-step instructions, timelines, and downloadable tools and templates for planning and hosting a successful event. Plus, users will learn the ins and outs of working with the media, creating press releases and PSAs, generating public interest, capturing the event with video and sharing it online. Learn more and/or download a free copy of the Farmer Field Day Toolkit at: http://www.sare.org/Grants/Farmer-Field-Day-Toolkit.

Farm Field Days

The farm field day season is underway, and many land grant universities and organic education and certification organizations offer a variety of opportunities to learn about organic farming in person. Here is a very small sampling of some of the many field days that are happening around the country:

Training Webinar for Organic Certified Handlers

On June 14, 2017 at 1-2PM Eastern Time, the Agricultural Marketing Service (AMS) National Organic Program (NOP) is holding a one-hour training webinar for organic handlers. The topic is Organic Integrity in the Supply Chain. Organic handlers play a vital role in the global organic control system, which includes strict production standards; accreditation of certifiers; certification of farmers, processors and handlers; and enforcement. AMS has identified violations of organic regulations involving shipments of soybeans and corn entering the U.S. and enforcement actions are underway. We are investigating other evidence related to other shipments of soybeans and corn. To help guard the integrity of organic imports, this training webinar focuses on the role of organic system plans and recordkeeping systems in ensuring organic integrity of imports, and highlights critical control points that will be audited during inspections. Register at: https://cc.readytalk.com/r/wdqfaqcl01c2&eom

eOrganic Mission

eOrganic is a web community where organic agriculture farmers, researchers, and educators network; exchange objective, research- and experience-based information; learn together; and communicate regionally, nationally, and internationally. If you have expertise in organic agriculture and would like to develop U.S. certified organic agriculture information, join us at http://eorganic.info.

eOrganic Resources

Find all eOrganic articles, videos and webinars at http://extension.org/organic_production

Connect with eOrganic on Facebook and Twitter, and subscribe to our YouTube channel!

Have a question about organic farming? Use the eXtension Ask an Expert service to connect with the eOrganic community!

 

eOrganic logo 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 22815

July 2017

lun, 2017/07/24 - 11:54
New Fire Blight Management Article

This new eOrganic article contains the most up-to-date information on managing Fire Blight organically in the western U.S. Learn how to identify the disease, how it spreads on fruit trees, which cultivars of apple and pear are more or less susceptible, and how to manage the disease with an integrated program. This article was produced by members of a NIFA OREI funded research project entitled Implementation of Non-Antibiotic Programs for Fire Blight Control in Organic Apple and Pear in the Western United States. Read the article here.

New Video on Identifying Syrphid Fly Larvae

A new eOrganic video can help you identify syrphid flies and distinguish the larvae of these important aphid predators from caterpillars. It will also give you some tips on how to make your farm more hospitable to syrphids (also known as hoverflies), each of whom can consume hundreds of aphids. This video was created as part of the NIFA OREI funded project entitled Biodiversity and Natural Pest Suppression (BAN-PestS) led at Washington State University. Watch the video here.

New Webinar Explains Different Types of Corn

On September 27th at 10AM Pacific Time, eOrganic will host a webinar entitled Hybrid, F1, Double Cross, and Open-pollinated Corn: What Does it All Mean? Intended Audience: Anybody with an interest in different types of corn varieties and their relative merits. In the webinar, presenters Margaret Smith of Cornell and Richard Pratt of New Mexico State University will explain what different types of corn varieties are, how uniform or variable each type is, and highlight the relative advantages and disadvantages of the different variety types.This presentation is part of the NIFA OREI funded project Breeding Non-Commodity Corn for Organic Production Systems. Register for the webinar here.

Survey on Post-harvest Quality and Food Safety of Organic Produce

A group of researchers from Purdue and other U.S. universities is conducting a project to study best management practices for enhancing post-harvest quality and safety of organic produce/vegetables. The goal of this study is to identify the needs and issues associated with organic produce/vegetables and their quality and safety. Subsequently, this will help identify the research and extension priorities associated with safety and quality of organic produce. This work is supported by the USDA National Institute of Food and Agriculture, grant project #1007457. This information will not only be useful to you and your business entity, it will also be useful to other organic stakeholders including researchers and policymakers. This study has been approved by Purdue’s Institutional Review Board. The entire survey is designed to take approximately 25 - 30 minutes. Your participation is strictly voluntary and your response to the survey will be anonymous. Responses to the survey will be aggregated to prevent the disclosure of organization or farm specific data. Please visit this link below or scan the QR code to go to the survey. If needed, you may also copy and paste the link in your web browser. https://purdue.qualtrics.com/SE/?SID=SV_01hJsknL95IIgM5

Submit Your Ideas for the Organic Seed Growers Conference Today

The Organic Seed Alliance invites you to help shape the 9th Organic Seed Growers Conference by providing proposals for content. This is your opportunity to share important research and ask timely questions related to organic seed. The conference is the largest organic seed event in the U.S. and provides two days of presentations, panel discussions, and networking events. We welcome your proposals for presentations, workshops, posters, panels, and roundtables. The deadline is today July 24, 2017. The conference will take place from February 14-17, 2018 in Corvallis, Oregon. Find out more information here.

Bee Better Certification Program

The Xerces Society for Invertebrate Conservation has partnered with Oregon Tilth to develop and launch the Bee Better Certified™ program, a new certification program that enables agricultural producers to let consumers know they are farming in ways that benefit bees. Bee Better Certified™ works with farmers and food companies to conserve bees and other pollinators in agricultural lands. Our work advances more resilient pollinator populations and sustainable crop production. The Bee Better Certified seal identifies and celebrates farmers and businesses that adopt farm management practices that support pollinators, and gives consumers confidence that their purchasing decisions benefit pollinators and the farmers working to protect them.To find out more about this program, visit the Bee Better Certified website.

Organic Certification Cost Share Still Open

You can still apply for 2017 Organic Certification Cost Share funds until October 31, 2017 if your organic operation is in the United States and you applied for organic certification from October 1, 2016 and September 30, 2017, you may receive up to 75 percent of certification costs, not to exceed $750 per certification scope.Find out more about this program by contacting the responsible agency in your state which you can find here

NOSB Web Meeting on Hydroponics

The National Organic Standards Board (NOSB) will meet via conference on August 14, 2017 from 1:00pm - 3:00pm Eastern to discuss hydroponics in organic food production. The NOSB will not be voting on a recommendation during this web conference. A transcript will be available approximately two weeks after the event. The NOSB is a federal advisory committee established by the Organic Foods Production Act of 1990 and administered through the Agricultural Marketing Service (AMS). The NOSB recommends whether substances should be allowed or prohibited in organic production, handling, and processing, and advises the Secretary of Agriculture on other aspects of the organic regulations.Register for the web meeting  at: https://cc.readytalk.com/r/3itgag2r7btt&eom

Recent Organic Research Articles

Kissing Kucek, L. et al. 2017. Evaluation of wheat and emmer varieties for artisanal baking, pasta making, and sensory quality. Journal of Cereal Science Volume 74, March 2017, pp. 19–27. Available online at https://doi.org/10.1016/j.jcs.2016.12.010.

Lehnhoff, E.; Z. Miller, Z., P. Miller, S. Johnson, T. Scott, P. Hatfield, F. D. Menalled. Organic Agriculture and the Quest for the Holy Grail in Water-Limited Ecosystems: Managing Weeds and Reducing Tillage Intensity. Agriculture 2017, 7, 33. Available online at: http://www.mdpi.com/2077-0472/7/4/33?utm_source=TrendMD&utm_medium=cpc&u...

Martina, L. S. Symanczik; P, Mäder, G. de Deyn,  and A. Gattinger. 2017. Organic farming enhances soil microbial abundance and activity: A meta-analysis and meta-regression. PLoS ONE, 12 (7), pp. 1-25. Available online at https://doi.org/10.1371/journal.pone.0180442

Silva, E.M.; K. Delate. 2017. A Decade of Progress in Organic Cover Crop-Based Reduced Tillage Practices in the Upper Midwestern USA. Agriculture 7, 44. Available online at: http://www.mdpi.com/2077-0472/7/5/44/htm

Organic Mission

eOrganic is a web community where organic agriculture farmers, researchers, and educators network; exchange objective, research- and experience-based information; learn together; and communicate regionally, nationally, and internationally. If you have expertise in organic agriculture and would like to develop U.S. certified organic agriculture information, join us at http://eorganic.info.

eOrganic Resources

Find all eOrganic articles, videos and webinars at http://extension.org/organic_production

Connect with eOrganic on Facebook and Twitter, and subscribe to our YouTube channel!

Have a question about organic farming? Use the eXtension Ask an Expert service to connect with the eOrganic community!

 eOrganic logo 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23113

Organic Fire Blight Management in the Western U.S.

ven, 2017/07/21 - 20:20

eOrganic authors:

Tianna DuPont, Washington State University

Ken Johnson, Oregon State University

Rachel Elkins, University of California

Tim Smith, Washington State University

David Granatstein, Washington State University

Overview

Fire blight is an important disease affecting pear and apple. Nationally, annual losses to fire blight and the costs of control are estimated at over $100 million (Norelli et al., 2003). While fire blight rarely kills an entire orchard in the western states, the disease and its control still cause significant economic losses. In the Pacific Northwest and northern California, there have been minor outbreaks annually since 1991 with at least some production districts experiencing major outbreaks every 3 to 4 years. Even minor disease outbreaks can be significant. For example, a 10% incidence of rootstock blight in a 4-year old apple orchard can result in losses up to $3,500 per acre (Norelli et al., 2003).

The fire blight pathogen, Erwinia amylovora, is native to North America. In the western United States, most common infections ordinarily occur on secondary blooms in May or June during the weeks following petal fall. Occasionally, however, the damage is done during primary bloom. Fire blight has always been a serious disease of pear, and the susceptibility of this species to fire blight is one of the reasons that United States pear production is concentrated in semi-arid regions of western states where dry summers lessen the impact of the disease. In apples, the danger of serious economic damage by fire blight has increased due to the adoption of high density orchard systems and widespread cultivation of susceptible scions on highly susceptible rootstocks.

Causal Organism

Fire blight is caused by Erwinia amylovora, a gram-negative, rod-shaped bacterium. It has appendages called flagella that allow it to swim in water. The bacterium grows by splitting its cells, and the rate of division is regulated by temperature. Cell division is minimal below 10°C (50°F), and relatively slow at air temperatures between 10°C and 20°C (50°F to 70°F). Above 20° C, the rate of cell division increases rapidly and is fastest at 27°C (80°F). Above 27°C, cell division slows and above 35°C (95°F), cell density on and in the plant can actually decline (Pusey and Curry, 2004). Colonies of pathogen cells on the host plant experience a wide range of temperatures each day, so the actual rate of colony growth varies from one moment to the next.

Signs and Symptoms Cankers

Areas of branch tissue diseased with fire blight are termed cankers. Generally, older cankers appear brown to black and dry. On older branches, the bark within the canker may be sunken. Cutting away the bark from the edge of an active canker reveals reddish flecking in the cambium and outer xylem adjacent to the canker margin. This flecking represents young infections expanding into the healthy tissues. As the canker expands, the diseased cambium dies, turns brown, and dries out (Teviotdale, 2011).

overwintering fire blight canker in pear

Figure 1. Overwintering fire blight canker in pear. Photo credit: Tianna DuPont, Washington State University Extension.

Flower Clusters

Flowers are frequently the first part of the plant infected by Erwinia amylovora. Generally, symptoms are first visible about two weeks after petal fall. Initially, the floral receptacle, ovary, and peduncles become water-soaked and dull grayish-green in appearance. Later, these tissues shrivel and turn brown to black. Similar symptoms often develop in the base of the blossom cluster and in young fruitlets as the infection spreads internally. During periods of high humidity, small droplets of bacterial ooze form infected tissue. Ooze droplets are initially creamy white, becoming amber- to red-tinted as they age (Johnson, 2000).

The characteristic “strike” symptoms that develop after floral infections may require up to 21 days to become noticeable. During this period of symptom development, the bacteria can move down and up the branch in xylem and phloem parenchyma cells, well ahead of the visible symptoms. 

Blossom symptoms 17 days after infection

Figure 2. Blossom symptoms 17 days after infection. Photo credit: Tianna DuPont, Washington State University Extension.

Shoots

The pathogen moves within the tree from flower infections to susceptible tissues such as nearby shoot tips. Succulent shoot tips may also be infected directly during hail storms or heavy rain. 

Diseased shoots wilt to form a symptom called shepherd's crook. Leaves on diseased shoots often blacken along the midrib and veins before becoming fully necrotic (blackened), and cling firmly to the host after death—a key diagnostic feature. Infections usually first appear on the 2-3 youngest, most tender non-expanded leaves near the shoot apex. These infections frequently progress down the limb, sometimes very quickly. Numerous diseased shoots give a tree a burnt, blighted appearance, hence the disease name.

Shepherds Crook, Ken Johnson OSU

Figure 3. Shepherd's crook symptom on shoot tips. Photo credit: Ken Johnson, Oregon State University.

Orchard with burnt appearance due to fire blight Tim Smith WSU

Figure 4. Orchard with burnt appearance due to severe fire blight. Photo credit: Tim Smith, Washington State University Extension.

Apple Rootstocks

Rootstock infections develop at the graft union as a result of internal movement of the pathogen through the tree from flower infections or, less commonly, from infections through water sprouts or burr knots. Bark of infected rootstocks may show water-soaking, a purplish to black discoloration, cracking, and signs of bacterial ooze. Red-brown to black streaking may be apparent in wood just under the bark. The timing of rootstock symptoms is typically mid- to late-season, but sometimes they develop in the spring of the following season. Symptoms of rootstock blight can be confused with Phytophthora collar rot. ELMA.26 and M.9 rootstock cultivars are highly susceptible to fire blight (Johnson, 2000).

Infection at graft union termed "rootstock blight" Tim Smith WSU extension

Figure 5. Infection at graft union termed rootstock blight. Photo credit: Tim Smith, Washington State University Extension.

Water soaking and bacterial ooze due to fire blight Tianna DuPont WSU Extension

Figure 6. Water-soaking and bacterial ooze as a result of fire blight in rootstock. Photo credit: Tianna DuPont, Washington State University Extension.

Red brown streaking fire blight Tianna Dupont WSU Extension
Figure 7. Red-brown streaking under the bark of diseased rootstock tissue. Photo credit: Tianna DuPont, Washington State University Extension.

The Disease Cycle Initial Source of Pathogen

Erwinia amylovora overwinters in cankers from the previous season. Pathogen cells survive primarily in canker margins where diseased bark tissue meets healthy tissue. In many of these cankers, the pathogen dies out over the winter, but in 20–50% of cankers, active cells of the pathogen survive until the next bloom period (van der Zwet and Beer, 1991). In spring, during periods of high humidity, the pathogen oozes out of the canker margins. A tiny droplet of this ooze (4 microliters) may contain 100 million to one billion cells (Slack et al., 2017)! Insects such as flies are attracted to this ooze as a food source (Ogawa and English, 1991), contributing to its spread.

Pathogen ooze from old cankers Tim Smith WSU Extension

Figure 8. Pathogen ooze from old cankers is attractive to insects, which vector the pathogen from old canker to flowers. Photo credit: Tim Smith, Washington State University Extension.

Dispersal of the Pathogen in Spring

Insects or windblown rain are the primary means by which the pathogen moves from old cankers to flowers. When insects visit oozing cankers and then feed on nectar in nearby flowers, they transfer the fire blight pathogen onto floral surfaces including the stigmas, which are nutrient-rich surfaces located at the top of the styles. In warm weather, pathogen cells reproduce rapidly on stigmas. Once a few blossoms are infested, honeybees, other insects, and rain can move the pathogen to additional flowers (Johnson et al., 1993; Pattemore et al., 2014). This stage of the disease cycle is termed the floral epiphytic phase, where epiphytic means bacteria living and growing on plant surfaces prior to infection.

Figure 9. Pathogen cells (1) multiply on the flower stigma (2) and if rain or dew occur are washed into the floral cup (3).

Infection of Flowers

Fire blight bacteria cells multiply on the stigma during the four to eight days the flower is open. If the weather is warm, the pathogen grows rapidly, forming a colony on the stigma. If the colony grows to greater than 100,000 cells, then the flower has a reasonable chance of being infected. In order for flowers to become infected, rain or dew must wash the pathogen cells from the floral stigma down the style into the floral nectary. The pathogen enters (infects) the flower near the base of the style by swimming through the small openings from which nectar is secreted. The infection begins in the developing fruitlet, and subsequently spreads down the petiole (stem) of the flower and into the cylinder of living cells (xylem and phloem parenchyma cells) located just between the bark and the wood of the tree, killing host tissues as it progresses (Momol et al., 1998).

Insects move the pathogen from flower to flower Tianna Dupont WSU Extension
Figure 10. Pollinating insects including bees move the pathogen from flower to flower. Photo credit: Tianna DuPont, Washington State University Extension.

Shoot Infections

Shoot blight infections generally occur later in the season, often during summer storms. Insects or windblown rain move pathogen cells from oozing cankers on trees within the orchard or from a neighboring orchard. Damage to young growth from hail, wind, or insects creates openings where bacteria can invade the plant (Biggs et al., 2008). Pathogen cells dispersed away from oozing cankers are viable for only a day or two and do not multiply again unless introduced to young tissues wounded by insects, wind, or hail. Occasionally, shoot infections also develop via internal movement of the pathogen through the xylem from a floral infection to the tip of a growing shoot.

Secondary Bloom

Secondary (rat tail) bloom refers to flowers that develop and open after the primary bloom. They are most abundant one to three weeks after full bloom, and are at high risk of developing fire blight. Late blooms are at high risk of infection because warm late-spring air temperatures are more conducive for bacterial growth and infection of flowers, and because the fire blight pressure in the orchard is higher. The intensity of secondary bloom varies from year to year and is difficult to manage horticulturally. Dwarfing rootstocks, in contrast to non-dwarfing rootstocks, tend to promote secondary flowering. Moreover, several widely-grown scion cultivars (e.g., Bartlett pear and Cripps Pink apple) can produce abundant secondary flowers.

Horticultural Risk Factors Tree Age

The younger the tree, the more damage that is likely to occur if it becomes diseased with fire blight. Cankers progress rapidly through young tissues and consequently, young trees. Once a branch is three to five years old, the rate of canker expansion slows.

Rootstock Blight

Young apple trees are also prone to the development of rootstock blight if the rootstock cultivar is highly susceptible to fire blight (e.g., M.9, EMLA 26) (Aldwinckle, 1998). Without causing symptoms, pathogen cells originating in cankers in upper limbs can move internally through the cambium and xylem to the graft union. If these dispersed cells are successful in re-initiating disease development at the graft union, rootstock blight occurs and kills the tree. Rootstock blight is most common up through the fifth leaf, and sometimes as late as the seventh leaf. After that, the frequency of this phase of the disease declines.

If the rootstock is no more susceptible than the scion variety (M.7, seedling), then rootstock blight symptoms are rare. An exception is Bud9 rootstock. In Bud9, fire blight generally does not develop at the graft union. However, Bud9 rootstock is susceptible when inoculated directly. This is a concern due to its prolific root suckering.

All ‘Geneva’ series rootstocks in commercial propagation, including those with dwarfing characters similar to M.9, are resistant to fire blight. Resistance in the rootstock is not transferred to the scion, however, and thus an infected scion cultivar on a Geneva rootstock can still be badly damaged by fire blight. However, damaged scions on resistant rootstock are much more likely to survive and regrow than die from a girdling rootstock infection. Rootstock blight is not a serious concern in pear.

Table 1. Rootstock Susceptibility to Fire Blight 

  Highly susceptible Moderately susceptible Moderately resistant Apple Alnarp Malling 7 EMLA Bemali Malling 9 Budagovsky 9 Budagovsky 490 Malling 26 Vineland 3 Geneva series Malling 27 Geneva 16 Malling 7 Mark Series   Robusta Ottawa   Vineland 1 Poland 2   Vineland 2 Poland 16   Vineland 5 Poland 22   Vineland 6 Vineyard 4   Vineland 7 Pear Provence quince   Pyrus betulaefolia ‘Old Home x Farmingdale’ Pyrus communis ‘Bartlett’   Pyrus calleryana Pyrus communis ‘Winter Nelis’   Pyrus communis ‘Old Home’     Pyrus communis ‘Old Home x Farmingdale’ Cultivar Susceptibility to Infection

Cultivar susceptibility to fire blight has a genetic component, but susceptibility is also linked to the flowering habit of the cultivar. However, there are no commercial cultivars of pear or apple that are immune to infection. Cultivars that bloom relatively early, or for short periods then quit for the season, frequently escape infection. Cultivars that bloom late, straggle out the primary bloom, or produce secondary (rat tail) flowers during late spring are infected more frequently (Ostenson and Granatstein, 2013).

Late "rat tail" blooms after primary blooms have formed fruitlets

Figure 11. Late ‘rat tail’ blooms after primary blooms have formed fruitlets. Photo credit: Tim Smith, Washington State University Extension.

Tree Vigor

Tree vigor is influenced by age, nutritional status, and crop load. For example, a young tree pruned heavily and supplied with lots of nitrogen to encourage vegetative growth is more likely to suffer extensive damage when diseased with fire blight than an older tree that is being managed to produce fruit. The common practice of pushing young trees with nitrogen fertilizer to “fill their space,” coupled with susceptible genetics, raises the risk for severe damage if fire blight occurs. It is important to note that moderating vigor will not prevent infection, but it will reduce damage done to the tree by expanding fire blight cankers.

Background Fire Blight Levels


A serious fire blight outbreak requires a nearby overwintering source of the pathogen, but this source does not have to be large and can be located in a neighboring orchard. For example, a single active, overwintering canker can produce enough pathogen cells to infest a one-acre area during primary bloom, even if the daily temperatures that promote pathogen growth on the flower stigmas are relatively cool (Thomson, 2000). Proximity to an overwintering canker increases the risk that new flowers will be infested with the pathogen and become diseased with fire blight. Incidence of the disease in the prior year is an important factor in assessing the risk of fire blight in the current year. During the summer, fire blight from current-season infections largely drives the risk of shoot infection and infections that occur as a result of storm damage.

Fire Blight Management Sanitation

Sanitation is an important aspect of fire blight management. Remove old cankers before the tree is shaped for structure in order to dispose of diseased prunings outside the orchard, eliminating them as an infection source in spring. Compared to pruning cuts made in summer, cuts in winter can be made closer to the visible canker edge because the pathogen is confined to the cankered area. Make the cut at the next horticulturally sensible site below the canker. Tools do not need to be sterilized when cutting on fully dormant trees. 
Some growers have effectively used blow torches (MAPP gas) to heat sterilize old cankers that were difficult to remove from the tree. When using a torch, the goal is to heat the cambium sufficiently to kill the bacterial cells. This temperature is approximately 140°F; i.e., when the tissue becomes too hot to touch. It is not necessary to completely blacken (char) the canker.

Late (delayed) dormant applications of fixed copper bactericides also provide a partial degree of orchard sanitation. The timing of a delayed dormant treatment is typically 2–4 weeks before bloom. The copper residue on the tree kills viable pathogen cells as they are released from old cankers, which slows the rate of buildup of the pathogen populations in flowers during bloom (Elkins et al., 2015).

During the spring and summer, it is advised to prune out fire blight infections as soon as they are observed, especially in younger trees. The observation of an active canker should also prompt inspections of other trees in the orchard. Pruning cuts to remove cankers in spring and summer should be made at 12–24 inches below the edge of the visible canker, with the longer distances used in younger trees with susceptible genetics. Removing a strike greatly reduces further damage to the tree, especially if the infection is removed at an early stage of development.

Orchard Environment

Heat drives the buildup of the pathogen population on flowers, and moisture triggers the infection event. Frequently, when a period of high temperature without rain occurs, new infections are limited to low areas (where dew is more likely to occur) in the orchard. These areas form dew earlier and for longer duration. As few as two hours of wetting by dew is sufficient to trigger infection if the temperatures preceding the wetting event were favorable for pathogen growth.

Anything that increases the relative humidity in an orchard (irrigation, frost control, dense as opposed to open tree architecture, cover crops, weed growth, wind breaks) increases the risk of a fire blight outbreak. It is particularly important to limit sprinkler irrigation when flowers are open, which has been shown to be an important trigger of blight outbreaks. Several studies have shown that pear and apples trees are not impacted or stressed by reducing the frequency of irrigation during the bloom and post-bloom periods. A little soil drying is actually beneficial, assuming trees are then well-watered during the more stressful summer period. It is unlikely that the trees can be overly stressed during the few days of peak fire blight risk at full bloom to petal fall and warm temperatures. Keep the intervals between irrigation as long as possible, and let the soil surface dry.

Removal of Flowers

Most fire blight outbreaks begin from flower infections. In a new orchard, the chance of infection is greatly reduced by removing blossoms (by hand or lime-sulfur thinning). Hand removal of flowers may take 2-3 hours per acre on first- or second-year trees. This expense needs to be weighed against spraying the orchard (perhaps multiple times) and the costs of labor and tree replacement if an outbreak occurs. Many organic growers successfully use the blossom removal method to prevent fire blight from developing in secondary blooms on their young pears and apples.

Predicting Risk

Fire blight outbreaks occur when open flowers experience summer-like weather. Daily high temperatures of 70–90°F promote rapid pathogen growth on floral stigmas, and flower-to-flower dispersal by insects. When warm days occur consecutively, the danger of infection increases. When temperatures are favorable for pathogen growth, their populations can double every 20–30 minutes. With sufficient numbers of pathogen cells (> 100,000 per flower), infections can occur within minutes. Moisture from rain or dew immediately after a warm period enhances the likelihood of infection.

Weather-based risk models can predict potential fire blight infection risk. Examples include ‘Cougar Blight’ (widely used in Washington and Oregon), ‘Zoller’ (California), and ‘MaryBlyt’ (eastern U.S.). These models track heat unit accumulation above a critical temperature (60–65°F) over periods of several days to make an infection risk determination. Moisture events and the presence of fire blight in or near the orchard are also considered in the assignment of an infection risk category; e.g., low, moderate, high, extreme, and exceptional risk. Many growers and advisers find the weather models most useful for determining spray intervals (tightening or expanding) and planning when to spray, especially when used in conjunction with forecasts of temperature.

After bloom, as the season progresses, air temperatures are nearly always conducive to pathogen growth and infection (Fig. 12), but fewer open flowers are present. During this period, it is important to continue monitoring weather forecasts for potential strong winds, rain, and hail events. Prior to and directly after storms is an important time to protect young trees and be prepared to monitor orchards and prune out new infections after storms occur.

Figure 12: Fire blight populations in flowers tend to be higher near petal fall than early bloom because of the time it takes for pathogen reproduction and dispersal, and because of higher temperatures late in bloom. Pathogen inoculum availability makes rat tail flowers particularly prone to infection. Data in above chart from Elkins et al. (2015).

Integrated Control for Protection of Susceptible Trees

Most pear cultivars and many of the consumer-popular apple cultivars are susceptible to fire blight, and consequently require a spray program to protect the trees in addition to cultural management described above. In general, spray programs for organic orchards are more intensive than contrasting programs for conventional orchards because organic growers are prohibited from using antibiotics to suppress infection. Integrated, non-antibiotic fire blight programs use the disease cycle to time the sequence of materials to target phases of pathogen activity during the season.

Use the Disease Cycle to Inform Choice of Material

A disease cycle depicts the life cycle of a pathogen and contains clues to management. We can use it to guide ways to interrupt the life cycle, and slow or stop the pathogen from proliferating in an orchard. The simplified fire blight disease cycle (Fig. 13) shows that the pathogen overwinters in old cankers. Then insects or wind/rain move the pathogen to the flowers where pathogen cells multiply and spread to the next flower at a rate determined by temperature. Oozing infections in flowers then provide inoculum for secondary infection of late bloom, shoots, and rootstocks. This disease cycle also shows approximate timings of non-antibiotic materials and how they can be integrated and sequenced to achieve effective disease suppression.

 

Figure 13. The fire blight disease cycle showing timing for integrated control. Figure credit: Tianna DuPont.

Choose the Most Effective Materials at Each Timing

Delayed dormant (2–4 weeks before bloom): Application of a fixed-copper bactericide provides a partial degree of orchard sanitation by killing pathogen cells as they are released from overwintering cankers. This reduces the primary inoculum and delays the pathogen's colonization of the flowers. A delayed dormant application of a fixed copper is recommended only if fire blight was present in the previous orchard season.

Early bloom: For apples in semi-arid production regions, lime sulfur is commonly sprayed in early bloom to thin flowers and manage fruit load. Lime sulfur used for thinning is also bactericidal and protects trees during the early bloom period. Biologicals such as Blossom Protect™ are also applied during early bloom. Blossom Protect™ is a living yeast that colonizes both the stigma and the nectary, competing with the fire blight pathogen for nutrients and space. In this competitive environment, the pathogen is less likely to attain a population size sufficient to cause infection. In general, the decision to use a biological material such as Blossom Protect™ is strategic and made independent of weather-based risk determinations. It should be applied after the last lime-sulfur thinning spray (a 1-day interval is sufficient).

Full bloom to petal fall: In the latter half of bloom, Bacillus-based biorationals (e.g. Serenade® Opti) and soluble coppers (e.g., Cueva®, Previsto®) are used to protect the flowers from infection. They are best used during this period because they establish a protective residue on the surface of the nectary. In contrast, during early bloom when stigmas need to be protected, these materials do not penetrate sufficiently into the nutrient-filled cavities of the stigmas to suppress pathogen buildup on this tissue. Disease risk models such as Cougar Blight are most useful during the full bloom to petal fall period to aid decisions on when and how often to spray. Generally, soluble copper materials show higher efficacy than Bacillus-based biorationals, but the soluble coppers pose a greater risk of causing fruit russeting, the severity of which is dependent on cultivar-sensitivity and the presence of moisture during or just after spraying.

The above sequence of non-antibiotic materials (lime sulfur, then yeast, then non-antibiotic chemical) is termed integrated control. While a given material alone may not be sufficient to manage fire blight in the orchard, a combination of materials at the right timings can provide control similar to or better than antibiotics.

IMPORTANT: Before using any pest control product in your organic farming system:

  • Read the label to be sure that the product is labeled for the crop and pest you intend to control, and make sure it is legal to use in the state, county, or other location where it will be applied.
  • Read and understand the safety precautions and application restrictions.
  • Make sure that the brand name product is listed in your Organic System Plan and approved by your USDA-approved certifier. If you are trying to deal with an unanticipated pest problem, get approval from your certifier before using a product that is not listed in your plan—doing otherwise may put your certification at risk.
  • Note that, although OMRI and WSDA lists are good places to identify potentially useful products, all products that you use must be approved by your certifier. For more information on how to determine whether a pest control product can be used on your farm, see the related article, Can I Use This Input On My Organic Farm?

 

Figure 14. Examples of integrated control programs. Blossom Protect™ followed by non-antibiotic chemical materials provided a high level of control.

Why Is It Important to Follow an Integrated Program?

In conventional systems, antibiotic-based fire blight management can rely more heavily on weather-based risk models to determine the need for sprays. In organic programs, where biological materials are important components, spray applications based only on the model warnings will likely be too late to achieve effective control. In order to be competitive, biologicals need to grow their populations on the flowers before fire blight pathogen cells arrive in order to be competitive. This may take two to four days. Additionally, by integrating multiple preventative materials we are able to target the pathogen at each stage of its life cycle and gain overall better control.

How Does an Integrated Program Vary Among Western States?

Lime sulfur for crop load thinning has become common practice in semi-arid regions of central Washington. Its use, however, is less common in other states and is not used in pears. Although growers at higher elevations (Idaho, Utah) do chemically thin flowers and some use lime sulfur, some have been concerned about frost events after bloom begins, and are therefore reluctant to chemically burn off the flowers that open later in bloom. In more humid regions, the degree of burn that results from a lime sulfur application is less predictable (more variable), and thus it has received less adoption in these areas.

The length of the bloom period varies from region to region, with fire blight being more difficult to control when the bloom period is long. In California, for example, because the trees receive fewer chilling hours in winter than trees grown farther north, the bloom tends to be longer with a straggly and untidy ending to the period of open flowers. Long bloom periods are especially prone to infection because the fire blight pathogen can build to very high populations when given this additional time.

Areas with higher humidity, such as the primary pear-growing areas of Oregon, have a higher likelihood of fruit russetting than drier regions of central Washington. Consequently, soluble coppers should be applied when conditions promote drying of the material. Moreover, at least in one case, the yeast material, Blossom Protect™, has also been implicated as a cause of fruit russetting in a high humidity environment. As a general rule, russet risk is higher in smooth skin pears than in apples. And, in higher humidity areas, more reliance needs to be placed on fruit-safe materials. Bloomtime® Biological is a fruit-safe biological that can be substituted for Blossom Protect™ during the early bloom period. It affects pathogen growth on the stigma, but does not interrupt the infection in the nectary. In the latter half of bloom, Bacillus-based biopesticides (i.e. Serenade® Opti) are considered russet safe alternatives to soluble coppers. A drawback of Bacillus-based biopesticides is that the effective residual (days of protection after application) is only 2–4 days compared to 4–6 days for soluble coppers.

Tips For Use of Blossom Protect™
  • Apply to every row. Research has found better colonization of flowers by A. pullulans when it has been spray-applied to the whole tree. Yeasts that colonize pome flowers do not appear to spread flower-to-flower as well as bacteria.
  • Apply early. Applications during early bloom (30–70%) allow sufficient time for the yeast population to grow, which leads to more effective control.
  • Use buffer. Applications with the companion material, Buffer Protect™, have shown significantly better control than with Blossom Protect™ alone.
  • Reapply after lime-sulfur. Lime sulfur applications are both anti-bacterial and anti-yeast and will affect the populations of an applied biological. Reapply after lime sulfur treatment, or wait to use Blossom Protect™ until after lime sulfur.
Example Organic Spray Program

(Johnson and Temple, 2013; Johnson et al., 2014)

  1. Delayed Dormant (just prior to green tip): Fixed copper sanitation if fire blight was in orchard last year (4–6 lb/A).
  2. Early bloom apple (crop load thinning): Lime sulfur during early bloom applied for crop load thinning is a strong anti-microbial. The lime sulfur percentage (2-10%) is based on the specific crop thinning goal. Reapply biological if lime sulfur goes on after the biological.
  3. Early bloom pear and apple: Blossom Protect™: One full application (every row) at maximum label rate, or if blight was in orchard last year, two full applications. In apple, apply Blossom Protect™ immediately after the second lime sulfur thinning spray. In smooth-skinned pears in wetter areas, russet risk from Blossom Protect™ might be unacceptably high. Bloomtime® Biological is an alternative, fruit-safe biological material. Note: biologicals, unlike antibiotics, should be applied preventatively. They need time to build their populations on the flowers. Waiting for the model to predict a high risk of infection is likely too late.
  4. Full bloom to petal fall:Spray treatments during this period can be guided by weather-based infection risk models (i.e. ‘Cougar Blight’ Washington and Oregon, and ‘Zoller’, California). Depending on the cultivar russet risk and the model:
    • Serenade® Opti every 2–4 days (most fruit-safe)
    • Or for improved control, mix Serenade® Opti with Cueva® (2–3 qt/A), or use Cueva® (3–4 qt/A) or Previsto® (3–4 qt/A) every 4–6 days. (The latter option is least fruit-safe for russet). Rates on the higher end of labeled rates have been most successful in field trials.
Consideration of Russet Risk

A drawback of non-antibiotic materials for fire blight control is that slow drying conditions after treatment can increase the risk of fruit russetting, which is a superficial damage to the skin of the developing fruit. This damage can reduce marketable grade of mature fruit. The period of highest russeting sensitivity is during the month following petal fall when fruit size is expanding rapidly (and thus fruit cuticles are very thin). Notably, soluble coppers and the yeast material, Blossom Protect™, have increased russet severity in some situations. Generally, a russet-tolerant apple cultivar grown in an arid environment is less prone to russet injury than a sensitive pear in a wet climate (Johnson, 2016). In most of central Washington, for example, the arid climate greatly reduces the risk of fruit russeting, and consequently Blossom Protect™ has shown a negligible russet risk in this area. Soluble coppers (i.e. Cueva® and Previsto®) carry a somewhat higher russet risk. A key to using these materials during periods of high russet sensitivity is to make spray application under weather conditions that promote rapid drying of the materials on the tree.

Smooth-skinned pears are much easier to russet than apples. Pear cultivars range in sensitivity to russet from Comice and d'Anjou (very sensitive) to Bartlett (moderately sensitive) to Gem (resistant). Sensitive apple varieties include Golden Delicious, Opal, Fuji, and Jonathan. 

Russet Risk Potential

Figure 15. Russet Risk of Possible Fire Blight Materials.

Specific Chemical and Biopesticide Materials

In the last few decades, numerous non-antibiotic products have been developed, registered with the EPA, NOP-approved, and marketed to orchardists for fire blight control (Table 2). The chart below shows materials that have received considerable research evaluation, and generally provided consistent and positive fire blight suppression.

Table 2. Materials Registered, Marketed and Approved for Organic Fire Blight Control 

Biologicals Active Ingredient Product effectiveness BlightBan® A506 freeze-dried Pseudomonas fluorescens A506 poor to fair Bloomtime® Biological freeze-dried Pantoea agglomerans E325 poor to good Blossom Protect™ dried spores of Aureobasidium pullulans ApCF10 and ApCf40 good to very good  Biorationals     Serenade® Opti    Anti-microbial molecules produced by fermentation of: Bacillus subtilis QST 713  fair to very good Others Bacillus spp. fair to good Soluble coppers     Cueva® copper soap copper octanoate, 1.8% metallic Cu, pH 7.0 good to very good Previsto® Copper-ammonium-alginate complex, 2.9% metallic Cu, pH 10.6 very good to excellent Fixed coppers     Several, e.g. Badge® X2 Copper oxychloride 25% and copper hydroxide, 28% metallic copper, pH 7.6 good when used for pre-bloom sanitation

Biologicals are preparations of living microorganisms (gram negative bacteria and yeasts) that produce colonies on the stigmas and nectary surfaces when applied to open flowers. These microorganisms are most appropriate during early bloom to slow the pathogen buildup during the epiphytic phase. Insects continue to move them to flowers that were not open at the time of treatment.

Copper materials vary in the form and amount of metallic copper (the active ingredient). Fixed-copper products have a longer residual time and are generally used for delayed dormant (green tip) and summer shoot blight protection in young, non-bearing orchards. In fixed coppers, most of the copper is insoluble with copper ions released slowly over time. Application of low-pH materials (e.g., Buffer Protect™) to trees treated recently with a fixed copper can cause a large release of copper ions and increase the potential for phytotoxicity (Rosenberger, 2011).

Soluble coppers. Newer copper formulations are designed to reduce copper phytotoxicity and fruit russeting potential by introducing far fewer copper ions to the plant surface and adding safeners that also reduce injury potential. Examples are Cueva® (copper octanoate)—a salt of copper and a fatty acid (copper soap)—and Previsto®—copper ions in a matrix with alginate (polymer from seaweed) designed to reduce risk of injury to developing fruitlets. Both Cueva® and Previsto® have shown little phytotoxicity in semi-arid Washington trials, but have shown some risk of russeting in wetter areas of Oregon and California. Cueva® is compatible in tank-mixes with Bacillus-based biopesticides, while Previsto® is not, due to its high pH.

Biorational is a term applied to Bacillus-based biopesticides, of which Serenade® Opti has the longest track record. Biorationals are considered to be non-russeting, fruit-safe materials. These biopesticides are made by fermenting strains of Bacillus spp. The activity against fire blight bacteria comes mostly from anti-microbial molecules produced by these bacteria during fermentation, in contrast to biologicals such as Bloomtime® Biological or Blossom Protect™, which colonize the flowers. Most of these products have both anti-bacterial and anti-fungal activity.

References and Citations


 

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 22646

Hybrid, F1, Double Cross, and Open-pollinated Corn: What Does it All Mean?

ven, 2017/07/21 - 11:38

Join eOrganic on September 27th, 2017 for a webinar about different types of corn: Hybrid, F1, Double Cross, and Open-pollinated Corn: What Does it All Mean? The intended audience is anybody with an interest in different types of corn varieties and their relative merits. In the webinar, corn breeders Margaret Smith of Cornell University and Richard Pratt of New Mexico State University will explain what different types of corn varieties are, how uniform or variable each type is, and highlight the relative advantages and disadvantages of the different variety types. This webinar is part of the NIFA OREI funded research project Breeding Non-Commodity Corn for Organic Production Systems.

The webinar takes place at 10PM Pacific, 11 Mountain, 12 Central, 1 Eastern Time. Advance registration is required.

Register now at https://attendee.gotowebinar.com/register/7529761675392126977

System Requirements

View detailed system requirements here. Please connect to the webinar 10 minutes in advance, as the webinar program will require you to download software. To test your connection in advance, go here. You can either listen via your computer speakers or call in by phone (toll call). Java needs to be installed and working on your computer to join the webinar. If you are running Mac OSU with Safari, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar, and if it isn't working, try Firefox or Chrome.

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 23193

Video: Identifying Syrphid Fly Larvae: Important Beneficial Insects in Controlling Aphids

jeu, 2017/07/13 - 16:20

eOrganic author:

Carmen Blubaugh, Washington State University

This eOrganic video was created by members of a project of the USDA National Institute of Food and Agriculture, Organic Agriculture Research and Extension Initiative (NIFA OREI) entitled Biodiversity and Natural Pest Suppression (BAN-PestS). 

Video Transcript

Syrphid flies, also known as hover flies, are beneficial insects. The adult fly lays its eggs on leaves near aphid colonies. As adults, they are important pollinators feeding on a wide range of flowers. In their larval stage, they prey on aphids. Each larva that hatches can consume hundreds of aphids. Syrphid fly larvae are aggressive aphid predators. They are commonly considered to be the most important aphid predator in vegetable crops.

Identifying Syrphid Flies

There are many species of syrphids. The adult flies are usually yellow and black and thus resemble bees. However, like other flies, they only have one set of wings. As their namesake indicates, they can often be seen hovering above flowers or aphid colonies. The eggs resemble a grain of rice and are often laid singly on leaves.

The larvae are frequently confused with common caterpillar pests that feed on vegetable crops. Being able to distinguish between the caterpillar pest and the beneficial syrphid fly larvae is crucial as you make decisions about pest management on your farm. Luckily, there are a few simple features that will allow you to distinguish between syrphid fly larvae and caterpillars. The first thing to look for is whether or not the insect has legs. Syrphid fly larvae do not have legs and move in an undulating manner. Caterpillars have legs. If you are unsure if an insect has legs, try getting the insect to move. The legs will be apparent on a moving caterpillar.

Syrphid fly larvae have nondescript heads, no eyes, and no chewing mouthparts. Caterpillar pests have distinguishable heads with chewing mouthparts. Impressively, these blind legless syrphid fly larvae manage to consume entire aphid colonies. These are valuable creatures to respect and support on your farm.

Promoting Syrphid Flies on Your Farm

You can make your farm more hospitable for syrphid flies by planting flowers that provide nectar for adult flies, such as sweet alyssum. Studies in apple orchards and collards have shown that planting sweet alyssum greatly increased the population of syrphid flies, leading to reduced aphid infestations (Gontijo, Beers, & Snyder, 2013; Ribeiro & Gontijo, 2017). Research out of California has looked at how to most efficiently intercrop sweet alyssum to attract aphid predators to lettuce fields. Their work indicates that as few as 1 to 2 alyssum transplants per 50 lettuce transplants is sufficient (Brennan, 2015). 

Syrphid flies are an important aphid predator and pollinator to promote on your farm. Knowing a few identifying characteristics—no legs, eyes or chewing mouth parts—can help you distinguish these beneficial insects from caterpillar pests. Being able to identify these insects will assist you in making pest management decisions that support these important predators and pollinators.

Follow this link to find a user-friendly flier that will help you distinguish between specific syrphid species. https://calcorenetwork.sites.ucsc.edu/wp-content/uploads/sites/249/2015/10/SYRPHID-FLYER.pdf

References and Citations

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 22763

Video: Scouting Vegetable Crops: An Introduction for Farmers

lun, 2017/06/12 - 18:35

eOrganic author:

Carmen Blubaugh, Washington State University

This eOrganic video on scouting vegetable crops was created by members of a project of the USDA National Institute of Food and Agriculture, Organic Agriculture Research and Extension Initiative (NIFA OREI) entitled Biodiversity and Natural Pest Suppression (BAN-PestS). 

Video Transcript Introduction

What was the last crop you lost to a pest? When did you realize you had a problem? Many times we don’t know there is a problem until we are up close and personal with a crop. All too often that is at harvest.

Scouting is the routine monitoring of pest pressure in a crop. A scouting routine can help you identify problems in your field before they get out of control. In this video we will scout for cabbage aphid in brassica crops in the Pacific Northwest. However, the scouting principles and tips can apply to any crop or region.

What is Scouting?

Scouting is a systematic way to assess the health of your crop and threat of pest outbreaks without examining every plant. Scouting relies on sampling a subset of the field to collect data you can use to make informed management decisions. Scouting can reduce your inputs and crop losses, saving you money.

There are various tools used in scouting. The tool you will use depends on the crop and pest. Many pests must be trapped to monitor while others, such as cabbage aphid, can be observed on the crop without trapping. In this video we focus on visual observation, but many of the principles of scouting we cover will apply regardless of the scouting tool used.

To begin a scouting routine, start by researching the pests you are likely to observe and the corresponding beneficial insects. This information will help you identify which scouting tools are appropriate and when to begin scouting. Numerous extension resources are available that describe the community of pests associated with a particular crop in your area.

Scouting 101: Before Entering the Field

When you arrive at the field, commit your attention to scouting. Focus is required to capture signs of pests. First, make observations about the entire field. Look for areas that appear stunted or have a color variation. Notice any unique geographic features, such as a depression. These areas may have higher pest pressure. You will want to visit these areas.

Select a path through the field that will allow you to collect a random yet representative sample. One method is to travel through the field in a "w" pattern, selecting plants to sample randomly along that path. Adjust your path through the field to ensure you visit areas you have identified to be at higher risk for pest infestations. Record your path through the field so that on your next visit you can scout a different route. Each scouting trip, you will select a different random sample. On each scouting trip you may want to visit areas you suspect to have growing pest populations in addition to your random sample.

In the Field

When you reach your first sample, assess the plant overall and then start looking at the individual leaves. Look at both young and old leaves, and don’t forget to search both sides of the leaf. You will want to remove a few leaves for closer observation. Now look at any buds, flowers, or fruit. Depending on the potential pest, you may even use your harvest knife to cut open the stalk or unearth the plant so you can see the roots.

Record your observations and a numeric assessment of the pest. For example, a numeric assessment of cabbage aphid pressure is the average number of aphids per leaf. Select three leaves from different parts of the plant and record the number of aphids and aphid predators per leaf. Repeat for ten plants.

You will follow the same procedure each time you scout, but vary your path through the field and which plants you sample. Standardizing your collection method is necessary to accurately track pest pressure over time.

Calculate the average number of aphids and predators per leaf. Reviewing these averages from visit to visit allows you to determine whether or not the pest pressure is increasing, or if beneficial insects are effectively managing the pest. This information will allow you to determine if and when you need to take action to control the pest, in other words, your action threshold.

Your action threshold is the point at which you’ll experience economic loss if control measures are not pursued. Your action threshold depends on the cost of controlling the pest, the effectiveness of your control measure, the value of your particular crop, and the potential for the pest to cause damage that will impact your ability to sell the crop. These factors vary for different crops. For instance, tolerance for aphids may be higher on kale than broccoli since aphids can get into broccoli heads where they are protected from insecticide applications.

Action thresholds also change over time, as markets fluctuate. Ask your local extension educator for help identifying a recently published action threshold for your region and crop. Keep in mind that action thresholds are usually calculated without considering biological control by beneficial insects, and you may want to adjust your action threshold if you observe high rates of natural pest suppression.

Developing your Scouting Routine

Farming is a demanding occupation. To make sure scouting gets done, it is best to make scouting a habit. For instance, you could dedicate lunchtime Tuesday to scouting a few fields. Keeping a bucket of scouting tools easily accessible can help facilitate regular scouting. Must-have scouting tools include a pencil, paper, clipboard, tally counter, and camera.

Pest emergence and growth are each temperature-dependent, and vary with each crop. Check local extension resources to determine approximately when pests in your crop system emerge, and initiate your scouting routine accordingly.

Scouting is an important practice to do on your farm that will definitely pay off. Check out the Pacific Northwest Insect Management Handbook for up-to-date information on crop specific pests. There, you’ll find examples of action thresholds, local emergence times and other resources to help you prepare for and avoid pest outbreaks on your farm.
 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 22209

Pages