Brief Summary of Minutes of Annual Meeting

WERA-60 Minutes Tuesday, March 27, 2012 WERA-60 helped organize a Plenary Session (3/23/2012) at the 7th International IPM Symposium on Resistance Entitled: Embracing Laboratory and Field Definitions of Resistance and Reconciling the IRM Proactivity Paradox. The Plenary was followed by a WERA-60 Workshop Entitled: Pesticide Resistance in Arthropods, Plant Pathogens, and Weeds: A Growing Threat to IPM and US Agriculture Chaired by David Mota-Sanchez MI State University with speakers including: 1) Mark Whalon- Advances in the Arthropod Pest Resistance Database, 2) Blair Siegfried- GMOs and Resistance, 3) Meg McGrath- Fungicide Resistance in Vegetable Crops, 4) Carl Bradley, Univ. of IL, Dramatic Use Increase in Fungicides in Row Crops, and Bob Nichols US Cotton Council for David Shaw (who could not attend) The Glyphosate Weed Resistance Situation in SE US. The WERA-60 Annual Meeting followed the resistance Plenary and Workshop. WERA-60 Meeting Minutes: Submitted by Mark Whalon Secretary: The meeting opened with a discussion of the formal processes of WERA-60s annual cycle including the meeting process, minutes, initiatives and reporting. Discussion of the Consolidation of Federal Funding: Various IPM funding lines in the Farm Bill, IR-4, NIFA, and other sources were addressed. Attendees proposed and discussed various strategies for ensuring continued support for IPM and resistance management as an important component of IPM. Considerable concern was expressed that the rush to consolidate IPM funding lines in NIFA would lead to a dilution of IPM in all of its contextual applications. Those present expressed various issues adding support to the above concern. In the end, the groups consensus was to find a specific arena within the emerging NIFA where resistance and resistance management science could be supported. Various attendees addressed the scope of various disciplinary resistance situations and the need for resistance management as a stand alone responsibility in overall US agriculture. Various suggestions were made and discussed toward securing some form of stable funding for Resistance Management within the Farm Bill and NIFA. Katie Stevenson and others endorsed WERA-60s support for IR-4 and IPM while considerable consternation was displayed in the NIFA process within which resistance and resistance management may not be identified as a very significant undertaking in the stability and future of major and minor crops in the US. Peter Ellsworth commented that IR-4 had sufficient support, but resistance management would need a clear and persuasive positioning within the NIFA structure in order to emerge with any status or funding. Currently, Integrated Resistance Management (IRM) is neither included in AFRI nor NIFA explicitly. Therefore, WERA-60 clearly supports the inclusion of baseline support for: 1-Development of clear strategies to integrate existing and new crop protection tools into IRM systems 2-Inclusion of these critical IRM components of IPM in NIFA and AFRI funding. Considerable discussion was focused toward different ways to accomplish 1 & 2 above. The consensus of WERA-60 was that IRM strategies needed to be explicitly cited in NIFA, AFRI and perhaps IR-4 lines. In fact, WERA-60 supports the idea that IRM should be an earmark explicitly stated and included within these funding lines as a means of assuring proper attention to and management of resistance. Further, WERA-60 supports the idea that IRM, as a tactic within IPM, would best be served if it was specifically mentioned within NIFA, AFRI and/or IR-4. WERA-60 members had in mind a specific articulation of IRM as a sub-tactic within any sustainable IPM program in either row or specialty crops. WERA-60 members were encouraged by various participants to make their thoughts and suggestions available through the three remaining Listening Sessions upcoming. The WERA-60 meeting turned to future business, and specifically to the site of the 2013 WERA-60 meeting. After considerable discussion, it was decided to convene WERA-60 in the second week of January 2013 in San Antonio in conjunction with Belt Wide Cotton Meeting. Ending comments by WERA-60 members detailed various pathogen, arthropod and weed publications and upcoming sessions in professional societies. Meeting adjourned at 8:30 pm.

>>>>>>>>>>>>>>>>>>>>>> Symposium Session 7th International Integrated Pest Management (IPM) Symposium Introduction Among the objectives of the Multi-Regional Work Group, WERA 60 Management of Pesticide Resistance, are: to facilitate exchange of information among pest management disciplines on the evolution of resistance in pests, to elucidate factors that influence the rate of resistance evolution, and to formulate strategies and tactics that may be utilized to delay resistance. A specific means to facilitate information exchange is to organize and deliver scientific symposia on pesticide resistance management. To provide such a forum, Dr. David Mota-Sanchez of Michigan State University (MSU), assisted by Drs. Mark E. Whalon, Andrew Wyenandt, and Robert L. Nichols of MSU, Rutgers University, and Cotton Incorporated, respectively, organized, moderated, and/or presented papers at session R 20 of the 7th International Integrated Pest Management (IPM) Symposium held in Memphis, Tennessee on March 27-29, 2012. We estimate that 120 individuals attended the symposium. [A summary and abstracts representing the session as a whole and each of the individual presentations is provided in the attached file under Summary of Minutes, Minutes Attachment, Copy of Minutes.] Summary Report The session featured two presentations each on entomology, plant pathology, and weed science (total of six). The first paper presented for each discipline was an overview of resistance history, reporting procedures, and management strategies within the discipline. The second presentation for each of the respective disciplines covered an emerging resistance issue, current research findings concerning the resistance, and/or recommendations for its management. In addition, there were active discussions following several of the papers, and a general discussion of controversial issues at the conclusion of the session. >>>>>>>>>>>>>>>>>>>>>> State Reports [The full state reports, including figures and publications are in the attached file under Summary of Minutes, Minutes Attachment, Copy of Minutes.] >>>>Arizona<<<< Peter C. Ellsworth, Al Fournier, Bruce Tabashnik, Xianchun Li, John Palumbo Arizona Pest Management Center & Department of Entomology & William B. McCloskey, School of Plant Sciences, University of Arizona >>Stabilizing Cross-commodity Whitefly Management and Completing Transition to Novel Reduced Risk Chemistries This project was funded through a Pest Management Alternatives Program (PMAP) grant (Li, Palumbo, Ellsworth & Fournier), heavily leveraged through other resources (Arizona Cotton Growers Association, Cotton Incorporated and industry support). The project includes evaluation of baseline susceptibility and resistance risk to whiteflies for new novel chemistries, including cross-resistance potential with current management tools. We are also evaluating and comparing field efficacy, non-target effects and economic effectiveness of the new chemistries with standards in cotton, melon and vegetable crops against whiteflies. Based on this research we are in the process of developing a new, sustainable stakeholder-driven cross-commodity whitefly management program and will transfer this technology to growers and PCAs through a comprehensive outreach plan incorporating field demonstrations, print and online publications, face-to-face trainings and peer network dissemination. We are in the third year of this two-year project. Update: Assays of field-collected whiteflies conducted in Lis lab have shown a significant drop in mortality rates for acetamiprid-treated whiteflies over the past two years, ca. 60% median mortality in 2010 versus just 30% in 2011. Dr. Peter Ellsworth solicited feedback from pest control advisors at Extension meetings in late 2011 on their observations of field performance of acetamiprid, and got mixed responses, but most agreed that it isnt working as well as when it was introduced. Since 2005, performance for imidacloprid against whiteflies on vegetables has also declined, based on data from Dr. John Palumbo. We have examined the use patterns of available AIs across crops and have developed a draft concept that will be put up for discussion with industry reps and PCAs at an upcoming meeting. Impact: The anticipated impact is promotion of statewide adoption of cross-commodity pesticide use practices that will help sustain important chemical tools for whitefly management across key crops in Arizona. >>Statewide Whitefly (Bemisia tabaci) Resistance Monitoring Program Statewide monitoring of whitefly resistance to pyriproxyfen, buprofezin, neonicotinoids, spiromesifen and synergized pyrethroids has been conducted in Arizona for over a decade. Work previously done in Dr. Tim Dennehys lab is now being carried on by Dr. Xianchun Lis lab. Findings: Field populations of B biotype whitefly are still susceptible to buprofezin and spiromesifen, but have developed moderate levels of resistance to pyriproxyfen and synergised pyrethroids for several years. Both cytochrome P450 monooxygenases (P450) and glutathione S-transferases (GST) are involved in whitefly resistance to pyriproxyfen. In 2011, field populations of B biotype whitefly have also developed low to medium levels of resistance to neonicotinoids tested (imidacloprid and acetamiprid). Consistent with our lab bioassay results, complaints on the field efficacy of neonicotinoids have increased this year. Lab bioassays also show that such field-evolved neonicotinoid resistance decrease significantly after 2-3 generations lab rearing without exposure to neonicotinoids. Synergism experiments suggest that cytochrome P450 monooxygenases (P450) are involved in field-evolved neonicotinoid resistance. All these resistant populations are susceptible to novel chemistries including rynaxypyr, cyazypyr, spirotetramat, and pyrifluquinazon, based on current research. We have established the baseline susceptibilities of B biotype whiteflies to these novel insecticides. We have surveyed the distribution of Q biotype whiteflies in Arizona, a biotype of worldwide significance and often with severe resistances to a wide array of chemistry. As of this year, Q biotype whiteflies in AZ are still limited to greenhouse plants and ornamentals. We have detected two subclades of Q biotype, designated as Q1 and Q2, respectively. We have developed a PCR-RFLP technique to differentiate Q1, Q2, and B biotype whiteflies. We have also monitored the resistance of Q biotype whitefly populations collected from ornamentals. All Q populations we have tested are resistant to the insecticides currently used for control of the B biotype whiteflies. All of the Q populations we have tested so far are susceptible to cyazypyr and rynaxypyr. But we have 1-2 Q populations that are resistant to the other two novel insecticides, namely, spirotetramat and pyrifluquinazon. >>Large-Scale, Spatially-Explicit Test of the Refuge Strategy for Delaying Insecticide Resistance Work in this area was published in PNAS this year: Carrière, Y., Ellers-Kirk, C., Harthfield, K., Larocque, G., Degain, B., Dutilleul, P., Dennehy, T.J., Marsh, S.E., Crowder, D.W., Li, X., Ellsworth, P.C., Naranjo, S.E., Palumbo, J.C., Fournier, A., Antilla, L., Tabashnik, B.E. 2011. Large-Scale, Spatially-Explicit Test of the Refuge Strategy for Delaying Insecticide Resistance. Proceedings of the National Academy of Sciences DOI: 10.1073. http://www.pnas.org/cgi/doi/10.1073/pnas.1117851109 Abstract: The refuge strategy is used worldwide to delay the evolution of pest resistance to insecticides that are either sprayed or produced by transgenic Bacillus thuringiensis (Bt) crops. This strategy is based on the idea that refuges of host plants where pests are not exposed to an insecticide promote survival of susceptible pests. Despite widespread adoption of this approach, large-scale tests of the refuge strategy have been problematic. Here we tested the refuge strategy with 8 years of data on refuges and resistance to the insecticide pyriproxyfen in 84 populations of the sweetpotato whitefly (Bemisia tabaci) from cotton fields in central Arizona. We found that spatial variation in resistance to pyriproxyfen within each year was not affected by refuges of melons or alfalfa near cotton fields. However, resistance was negatively associated with the area of cotton refuges and positively associated with the area of cotton treated with pyriproxyfen. A statistical model based on the first 4 years of data, incorporating the spatial distribution of cotton treated and not treated with pyriproxyfen, adequately predicted the spatial variation in resistance observed in the last 4 years of the study, confirming that cotton refuges delayed resistance and treated cotton fields accelerated resistance. By providing a systematic assessment of the effectiveness of refuges and the scale of their effects, the spatially explicit approach applied here could be useful for testing and improving the refuge strategy in other crop-pest systems. >>No Herbicide Resistance Detected in Arizona Dr. William B. McCloskey investigates any claim of herbicide resistant weed populations in Arizona by collecting seed from suspected resistant populations and conducting herbicide trials side by side with known susceptible populations in the greenhouse. To date, there have been no confirmed instances of herbicide resistant weed populations in Arizona, including any resistance to glyphosate despite the presence of resistant weed populations in surrounding states. >>Tools for Evaluating Resistance Management Practices in Arizona We continue to develop data, tools and resources to support evaluation of IPM adoption, resistance management, and other pest management practices. This includes development of the Arizona Pest Management Center Pesticide Use Database in partnership with the Arizona Department of Agriculture. The database contains over 20 years of historical pesticide use reports, integrated with other useful resources. This effort has received a funding boost through three successful Arizona Department of Agriculture Specialty Crop Block Grants that will partially support a database specialist position for the next 2 years. We have integrated IRAC, HRAC and FRAC mode of action tables into the database that will help facilitate resistance-related data queries. Impact: These data are used to infer resistance risk for cross-commodity pest management, and help guide our recommendations to growers. Data were also used in part of the analysis for a study recently published in PNAS (Carrière et al. 2011). >>Education and Outreach Vegetable IPM Updates. Since January 2010, the Vegetable Crops IPM Leadership Team (Peña, Palumbo, Tickes, Matheron and Nolte) has published Veg IPM Updates on a biweekly basis. These updates deliver timely information to end-users via web, email and smart phone. Delivered 26 biweekly updates in 2011 and 7 in 2012 on insect, disease and weed management, often including resistance-related topics. These reached over 450 Arizona and California stakeholders by email list, and at least 300 stakeholders via the Arizona Crop Information Site (http://ag.arizona.edu/crops/vegetables/advisories/advisories.html). In addition, the same team has produced and posted 35 vegetable IPM videos to date (11 on insects, 15 on weed control, 3 on diseases and 6 Question of the week videos) and created video archive webpage at http://ag.arizona.edu/crops/vegetables/videos.html. Stakeholders have responded with enthusiasm about the quality and timeliness of these updates. We have seen a steady increase in attendance at educational meetings and a >2-fold increase in listserv membership for Veg IPM updates. Western Farm Press and Western Agri-Radio Network distributed these updates to over 20,000 readers. Field Crops IPM Shorts. The Field Crops IPM Leadership Team (Brown, Ellsworth, Ottman, Norton, McCloskey, Mostafa and Fournier) in summer 2011 began producing short, timely advisory pieces on field crops pest management and getting these out to the broadest audience possible. Field Crops IPM Shorts are one-page articles on timely topics of interest that include photos, data and/or graphics. We have produced 18 shorts so far. Topics so far have included natural enemies of cotton pests, selective insecticides, cotton pest thresholds, and a guide to glyphosate products for weed control and others. Some of these outputs touch on resistance topics, including one piece on Round-up Ready alfalfa. The pieces go out to at least 360 stakeholders via agent email lists, and have also been picked up each week and redistributed by Western Farm Press while some pieces have been distributed by the National Cotton Council and Southwestern Farm Press, reaching many tens of thousands of readers. The pieces are archived on the ACIS site at http://ag.arizona.edu/crops/cotton/agronomic_ipm.html. Arizona Crop Information Website. The ACIS website (http://ag.arizona.edu/crops/) hosts current information and publications for clientele on crop production and pest management, including resistance issues, and is a primary outlet for Extension outputs. The site also provides clientele with information about upcoming meetings and pesticide regulatory updates. Our ACIS email list includes about 300 participants, and is used to send updates to clientele on new extension publications, emerging pest or pesticide issues and upcoming events. Presentations, Outreach and Continuing Education. The Ag Team organized and delivered 28 extension meetings in 2011, including 6 Crop Pest Losses workshops, indoor meetings, tent talks and other field-based meetings. In addition, several faculty (including Ellsworth, Palumbo, Tickes and Matheron) delivered presentations at state and regional conferences including the Desert Agriculture Conference and the Southwest Agriculture Summit. At least 94 Arizona Dept. of Agriculture CEUs, 56.5 California Dept. of Pesticide Regulation CEUs and 19 Certified Crop Advisor CEUs were delivered. Attendees are very conservatively estimated at over 1,600 people. The Southwest Ag Summit held in Yuma in March 2011 attracted 760 participants including 131 students, and delivered 12 AZ, 12 CA and 12 CCA CEUs in the breakout sessions alone. Nearly every Extension presentation related to cotton or vegetable pest management in 2011 included information about resistance of key pests to insecticides and strategies for retaining efficacy of important management tools. So far in calendar year 2012, we have held 7 Extension meetings and one farmer field day conferring about 15 Arizona CEUs. >>>>Colorado<<<< Phil Westra and Scott Nissen Department of Bioagricultural Sciences and Pest Management Colorado State University 2012 saw significant research and outreach progress on glyphosate resistant kochia which was reported over a much wider geographic range including KS, CO, NE, SD, ND, and Alberta, Canada. Molecular research by Andrew Wiersma, a CSU MS graduate student, showed that in all cases, glyphosate resistant plants from many accessions over this geographic range, had increased copy number of the EPSPS gene  usually in the range of 3-9 copies which appears sufficient to confer resistance to a field labeled rate of glyphosate (.75 lb ae/acre). With increased EPSPS copy number came increased transcript abundance and increased detection of higher levels of EPSPS enzyme with an antibody. Andrew will pursue additional kochia transcriptome sequencing and bioinformatics at Michigan State University in the program of Dr. Robin Buell. We continue to work closely with KSU weed scientists on the glyphosate resistant kochia problem in the Central Great Plains. We have become a center for molecular kochia research for all parties dealing with glyphosate resistant kochia. We collaborated with several other scientists on a publication of gene amplification cross-generational stability in Palmer amaranth from North Carolina. Work has been initiated on the rapid necrosis response in glyphosate resistant giant ragweed in multiple populations from North America. Dr. Fernando Adegas, visiting scientist from Brazil, worked with Dr. Scott Nissen and the CSU weed science team on molecular aspects of glyphosate resistant sourgrass and horseweed. His research showed that glyphosate resistance in sourgrass is not due to glyphosate metabolism nor to a gene mutation nor to increased EPSPS protein expression. Key personnel on our Colorado resistant weed team include Drs. Scott Nissen, Dale Shaner (ARS), Chris Preston (University of Adelaide, Australia), Jan Leach, ASN Reddy, and Todd Gaines (U. of Western Australia). >>>>Georgia<<<< Katherine L. Stevenson Department of Plant Pathology University of Georgia >>Research on Fungicide Resistance in the Gummy Stem Blight Pathogen of Watermelon Didymella bryoniae, which causes gummy stem blight (GSB) of watermelon, has a history of developing resistance to fungicides, most recently the succinate-dehydrogenase-inhibiting (SDHI) fungicide boscalid (FRAC Group 7). Pristine, a formulated mixture of boscalid and the quinone (outside) inhibiting (QoI) fungicide pyraclostrobin (FRAC Group 11) worked well against D. bryoniae until resistance to boscalid was observed in the southeastern U.S. in the late 2000s. In laboratory assays, out of 103 field isolates of this fungus, 82 and seven were found to be very highly resistant (BVHR) and highly resistant (BHR) to boscalid respectively. Cross-resistance studies with the new SDHI penthiopyrad showed that the BVHR isolates were only highly resistant to penthiopyrad (BVHR-PHR), while the BHR isolates appeared sensitive to penthiopyrad (BHR-PS). Research was conducted to investigate the molecular mechanism of resistance in these two phenotypes (BVHR-PHR and BHR-PS) and to assess their sensitivity to the new SDHI fluopyram. A 456-bp cDNA amplified fragment of the succinate dehydrogenase iron sulfur gene (DbSDHB) was initially cloned and sequenced from two sensitive (BS-PS), two BVHR-PHR and one BHR-PS isolate of D. bryoniae. Comparative analysis of the DbSDHB protein revealed that a highly conserved histidine residue involved in the binding of SDHIs and present in wild-type isolates was replaced by tyrosine (H277Y) or arginine (H277R) in the BVHR-PHR and BHR-PS variants respectively. Further examination of the role and extent of these alterations showed that the H/Y and H/R substitutions were present in the remaining BVHR-PHR and BHR-PS variants respectively. Analysis of the sensitivity to fluopyram of representative isolates showed that both SDHB mutants were as sensitive to this fungicide as the wild-type isolates. The genotype-specific cross-resistance relationships between the SDHIs boscalid and penthiopyrad and the lack of observed cross-resistance between these fungicides and fluopyram should be taken into account when selecting SDHIs for gummy stem blight management. >>>>Michigan<<<< Mark E. Whalon, David Mota-Sanchez, Brittany Harrison and Rebeca Gutierrez Department of Entomology Michigan State University >>MSU Arthropod Pesticide Resistance Database Accomplishments. The occurrence of pesticide resistance frequently leads to the increased use, overuse, and even misuse of pesticides that pose a risk to the environment, phytosanitation, market access, global trade, and public health. It can also result in serious economic loss and social disruption. The economic impact of pesticide resistance in the US has been estimated at $1.4 billion to over $4 billion annually (Pimentel et al 1991, 1993). Arthropods have been evolving for millions of years to defeat natural toxins. Since the first written report of insecticide resistance was published in 1914 by Melander, 574 species, 338 compounds, and 10,357 cases of pesticide resistance have been counted (Figure 1), most of which have been recorded over the last 60 years of intensive pesticide use. Most of the cases were found in agricultural, forest and ornamental plants (65.9%). Another 30.6% occurred in medical, veterinary and urban pests. Only 3.1% of the cases reported described the development of resistance in natural enemies such as predators and parasitoids, 0.4% in other species such as pollinators, and non-target insects. Conventional insecticides (organochlorines, organophosphates, carbamates and pyrethroids) make up about 85.2% of the total resistance cases. We have observed that there is an increase in the number of resistance cases in groups of compounds with novel chemistries and modes of action such as insect growth regulators, avermectins, neonicotinoids, IGRs, bacterial agents (Bts) and spynosins, among others. In addition, the Insecticide Resistance Action Committee (IRAC) has reported resistance grouped by insecticide mode of action. These reports are hosted in our MSU arthropod pesticide resistance database at: http://www.pesticideresistance.org/irac/1/. The IRAC database content reflects the current working knowledge of a wide range of experts from industry, academia, and state and local cooperative extension, with IRAC making the ultimate decision on rankings of resistance status. IRAC makes no claim of completeness or accuracy because situations can change quickly due to many factors. 2) Impacts. Our database is visited frequently; recording about 500,000 visits to our web site (www.pesticideresistance.org) per year, and is perhaps one of the most complete databases in resistance of organisms to xenobiotics. It is our intention that this effort in reporting arthropod pesticide resistance should contribute to the design of better alternatives for resistance pest management; and in the end contribute to the worlds effort to reduce hunger, and improve human and animal health and food security. >>Resistant Pest Management (RPM) Newsletter Accomplishments and impacts. The Resistant Pest Management (RPM) Newsletter was developed to spread knowledge of resistance around the world. The goal of the RPM Newsletter is to inform researchers, industry workers, pesticide policy and field personnel worldwide of ongoing changes and advances in pesticide resistance management, provide an archival resource to national and international policy leaders, and enhance communication of ideas among resistance managers worldwide. Since its 1989 inception, the Newsletter has published over 680 articles, including 19 articles in 2011. The Bi-annual publication has over 1,150 electronic subscribers (mostly in government, industry and academia), and hard copies are now part of 58 libraries serial listings worldwide. Example countries with serial listings include the United States, Germany, Italy, the United Kingdom, India, Japan, Taiwan, Egypt, Kenya, Costa Rica, Australia, Malaysia, Pakistan and New Zealand. The newsletter has received 21,879 visitors since May 2012. >>>>Nebraska<<<< Blair Siegfried Department of Entomology University of Nebraska Summary: Resistance monitoring techniques developed at the University of Nebraska for detecting Bt resistance in the European corn borer are currently used in support of an annual resistance monitoring program. This effort provides a means for early detection of Bt resistance and is an essential component of Bt resistance management programs. Additional testing of new Bt toxins was initiated in 2009 development of diagnostic bioassays was initiated in 2011. Efforts to characterize Bt resistance have continued and have resulted in research results that will be important to future resistance management efforts. The availability of one of these strains has provided valuable information regarding the development of modified B t toxins that overcome a variety of resistance mechanisms. We continue to develop techniques for identification of Bt receptors in the gut of pest insects and potential modifications that may result from resistance development using next generation sequencing of the midgut transcriptome. We have also continued research to characterize field evolved resistance to Bt toxins in Puerto Rican populations of the fall army worm which represents one the first instances of control failures with Bt transgenic corn and have documented the existence of resistance alleles in North Amercian populations of FAW. Impact: Planting of Bt corn has increased dramatically since its introduction in 1996. Widespread adoption of the technology has caused increased selection pressures and place increased priority on development of sound resistance management practices. The identification of resistant strains and characterization of resistance among field populations will provide critical information to federal agencies that regulate the use of this technology and help ensure that the technology is used a sustainable manner. Bt resistance monitoring information provided by our lab is currently utilized by most of the major seed and biotechnology companies to support registrations of transgenic corn for both European corn borer. This project represents a number of collaborations. Specifically, scientists from USDA-ARS including Dr. Richard Hellmich and Dr. Brad Coates participated in a number of joint publications associated with this research. In addition, a number of graduate students including E. Pereira, C. Gaspers, A. Crespo, and S. Tan participated in this project and contributed research that formed part of their Ph.D. dissertations. >>>>New Jersey<<<< Andy Wyenandt Extension Specialist in Vegetable Pathology Department of Plant Biology and Pathology Rutgers University Fungicide resistance management in vegetable crop production continues to be a major focus in New Jersey as well as the rest of the mid-Atlantic region (PA, DE, MD, and VA). The 6th edition of the Fungicide Resistance Management Guidelines for Vegetable Crop Production in the mid-Atlantic Region will be published in 2012. Since 2007, over 10,000 of these guides have been distributed to growers, extension agents and specialists, crop consultants, and industry representatives throughout the region representing to our best estimates between 75,000 to 100,000 A of commercial vegetable production. >>>>New York<<<< Margaret Tuttle McGrath Cornell University >>Fungicide resistance in cucurbit powdery mildew Activities pertaining to fungicide resistance in cucurbit powdery mildew being conducted in New York are monitoring of resistance in production fields, evaluating fungicides at-risk for resistance, and determining baseline sensitivity for new fungicides. Fungicides are an important tool for managing cucurbit powdery mildew to avoid losses in quantity and/or fruit quality. This is the most common disease of cucurbit crops, which include pumpkin, squash and melon. Effective control necessitates products able to move to the lower leaf surface, where this disease develops best. Unfortunately these mobile products are prone to resistance development because of their single-site mode of action. Only 3 of the 5 fungicide chemical groups labeled for cucurbit powdery mildew in the US currently are recommended: FRAC Codes 3, 7, and 13. Resistance to FRAC Code 1 and 11 fungicides has been shown to be generally common through previous research conducted in NY. Spores of this pathogen (Podosphaera xanthii) can be dispersed by wind long distances enabling widespread dispersal of resistant strains. Research conducted since the last report has focused on determining fungicide sensitivity of pathogen isolates (individuals) obtained at the end of the growing season in 2011 from commercial pumpkin crops, research fields, and non-fungicide-treated garden squash. Sensitivity is being determined using a leaf disk bioassay for the 55 isolates from 12 populations. Leaves of pumpkin at the cotyledon stage are sprayed with a fungicide, then one day later disks are cut, put on water agar in a sectioned Petri dish (six disks per section), and inoculated by transferring spores to the center of each disk. Three fungicide doses are tested and compared to a non-treated control in each bioassay. Pathogen growth is assessed after 7-14 days. A few more bioassays are planned to complete this work. Results from 14 bioassays conducted so far are as follows. Based on bioassays conducted with Rally, a DMI (FRAC code 3) fungicide containing myclobutanil as the active ingredient, 20% of the isolates were able to grow on leaf disks treated with 40 ppm, 85% of the isolates tolerated 10 ppm, and 15% of the isolates were sensitive to 10 ppm. Bioassays conducted with Quintec (FRAC code 13) revealed that 24% of the isolates were able to grow on leaf disks treated with 40 ppm quinoxyfen (active ingredient), 78% of the isolates tolerated 10 ppm, and 22% of the isolates were sensitive to 10 ppm. Only 4% of isolates tolerated 500 ppm boscalid, an active ingredient in Pristine. Isolates tolerant of this concentration are considered resistant. Most isolates (61%) were sensitive to 100 ppm boscalid. Doses used in bioassays cannot be directly compared to rates applied by growers treating their crops because the dose is prepared as a concentration and applied to coverage while the rate growers use is based on acreage treated. The concentration in a spray tank varies with the gallonage used, which varies a lot. When the fungicides used in the bioassay are applied at the highest labeled rate at 50 gallon/acre, the dose of active ingredient in the spray tank is 300 ppm of myclobutanil for Rally, 212 ppm of quinoxyfen for Quintec, and 700 ppm of boscalid for Pristine.

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