WERA60: Management of Pesticide Resistance

(Multistate Research Coordinating Committee and Information Exchange Group)

Status: Inactive/Terminating

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SAES-422 Reports

Annual/Termination Reports:

[12/30/2013] [05/12/2015]

Date of Annual Report: 12/30/2013

Report Information

Annual Meeting Dates: 01/10/2013 - 01/10/2013
Period the Report Covers: 10/01/2012 - 09/01/2013

Participants

Brown, Lydia, University of Arizona ; Ellsworth, Peter, University of Arizona; Holtzer, Thomas (Administrative Co-Advisor), Colorado State University; Kurtz, Ryan, Cotton Incorporated; McCLoskey, Bill, University of Arizona; Nichols, Robert, Cotton Incorporated; Stevenson, Katherine L. (Chair), University of Georgia; Whalon, Mark (Acting Secretary), Michigan State University; Wyenandt, Andy, Rutgers University

Brief Summary of Minutes

Please see attached file containing minutes and State Reports.

Minutes Attachment:

Attachment

Accomplishments

>>>>>>>>>>>>>>>>>>>>>> State Reports [The full state reports, including figures and publications, are in the file attached under Summary of Minutes (Copy of Minutes) >>>>>>>>>>>>>>>>>>>>>> ^^^^WERA-060 Annual Report for Colorado<<<< Phil Westra & Dale Shaner, Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523 >>>Glyphosate Resistant Kochia. We have collected over 100 random samples of kochia from eastern Colorado where complaints of glyphosate resistant kochia have increased over the past 2 years. Kochia resistance threatens reduced till farming from the southern plains all the way into Canada. In our greenhouse testing, some kochia plants survive up to 6 pounds of Roundup per acre. The photo below shows 2 kochia lines (2 and 4) totally killed by glyphosate while line 3 is unaffected. Molecular research has confirmed that glyphosate resistant kochia plants have many more copies of the EPSPS gene and that this makes them able to survive high rates of glyphosate (figure 3). This means that we will need to better develop other herbicides to help control kochia in various crops including Roundup Ready crops. >>>Screening Feral Rye Response to Beyond Herbicide The goal of this experiment was to identify resistant accessions of feral rye throughout the state of Colorado, and from this data perform an ALS assay to look at this as one of the possibilities for the mechanism of resistance. We used several teams of students in July 2012 to collect feral rye seed from 111 sites in eastern Colorado (figure 1). Each site was georeferenced and a minimum of 150 mls of seed was threshed from each accession. Seeds were planted in rows in greenhouse flats filled with commercial potting soil, and then watered and fertilized to promote good germination and growth. Once the plants reached a height of close to 4 inches, we applied Beyond herbicide at 3 oz/acre, 6 oz/acre, and 12 oz/acre (photo 1). The highest labeled rate in the field for control of feral rye with imazamox is 6 oz/acre. After spraying and allowing them to regrow for about a week, we cut all of the plants an inch from the soil, and the resistant plants quickly showed re-growth. After allowing them adequate time for regrowth, about 1 month, we sprayed all of the treated flats with the 6 oz/acre rate. We did this in order to surely eliminate any susceptible biotypes that survived the initial treatment. After identifying possible resistant accessions, we performed an ALS assay to determine the inhibitory effect of imazamox on the resistant plants. Several feral rye accessions survived 12 oz/acre of imazamox, suggesting they would not be controlled by a field rate of the herbicide. From the assay we graphed optical density vs. herbicide concentration to see the amount of inhibition for a single susceptible accession (F1), and three resistant accessions. To date, this research with a large number of feral rye accessions from eastern Colorado shows a wide range of responses to a given rate of Beyond herbicide. Some are controlled by 3 oz/acre of Beyond, while others are not controlled by 12 oz/acre. Ongoing research will attempt to further characterize the reasons for these differences. >>>Glyphosate Induced Rapid Necrosis in Giant Ragweed We have assembled a collection of 20 accessions of giant ragweed from the US and Canada with three phenotypes exhibiting differential response to lethal rates of glyphosate; glyphosate susceptible, glyphosate resistant with a slow rate normal survival response, and glyphosate resistant exhibiting rapid mature whole leaf necrosis within 24 hours following treatment. It appears that glyphosate triggers very rapid cell death at the whole leaf level, thereby excluding glyphosate in treated leaves that die and drop off the plant. Immature leaves and meristem tissues do not exhibit this response. The response requires light, and is seen in accessions from multiple sites that are distant from each other. Molecular research shows no implicated mutation in the EPSPS gene from resistant plants, and there is no indication of overexpression of EPSPS protein. ^^^^2012 WERA60 Annual Report for Georgia<<<< Submitted by: Katherine L. Stevenson, Department of Plant Pathology, University of Georgia >>>Accomplishment: A two-day international workshop on "Fungicide Resistance Development in North America for the 21st Century" was held in August 2012 in Providence RI, in conjunction with the Annual Meeting of the American Phytopathological Society (APS). The meeting was organized and sponsored by the APS Pathogen Resistance Committee, three members of which (Katherine Stevenson, Meg McGrath, and Andy Wyendandt) are also active participants in WERA60. The workshop featured presentations from invited speakers from the major fungicide manufacturers and scientists working in the area of fungicide resistance in the major crops in North America, including tree fruits and nuts, vegetables, soybeans, corn, peanuts, sugar beets, turfgrass, ornamentals, and rice. This was the first workshop of its kind since 1987. The second edition of a book titled "Fungicide Resistance in North America" based on the proceedings from the workshop is currently in preparation, edited by WERA60 participants Katherine Stevenson, Meg McGrath, and Andy Wyendandt. >>>Impact: This workshop held in conjunction with the APS meeting provided a forum to highlight the current state of fungicide resistance in major North American crops and an opportunity to share information, discuss management strategies and focus attention on current fungicide resistance issues and attract interest and participation from a wider audience. >>>Accomplishment: Research was conducted on resistance of the fungal pathogen Didymella bryoniae, which causes gummy stem blight (GSB) of watermelon, to the quinone outside inhibitor (QoI) fungicide azoxystrobin. Azoxystrobin resistance in D. byroniae was first confirmed in 2001 and was found at high frequencies in Georgia watermelon fields by 2002. Azoxystrobin sensitivity in D. bryoniae (and many other fungal pathogens) is usually determined using conidial germination assays. However, mycelial growth assays are less labor intensive (do not require microscopic examination) and thus are more suitable for screening large numbers of fungal isolates. Experiments were conducted to compare the sensitivity of conidial germination and mycelial growth of Didymella bryoniae to azoxystrobin (AZO) to evaluate the potential utility of mycelial growth assays for detecting azoxystrobin-resistant isolates of D. bryoniae. Results provided evidence that mycelial growth assays on medium amended with 1.0 µg azoxystrobin/ml could be used to effectively discriminate resistant and sensitive isolates. Isolates with relative growth values e0.90 are AZO-R and isolates with relative growth values d0.70 are AZO-S. >>>Impact: A simple mycelial growth assay using a discriminatory concentration of 1.0 µg/m azoxystrobin serves as an efficient tool for monitoring the frequency of azoxystrobin resistance in populations of the gummy stem blight pathogen and evaluating various fungicide programs for GSB management that include azoxystrobin (or other QoI fungicides). >>>Accomplishment: Resistance of the cucurbit gummy stem blight pathogen, Didymella bryoniae, to succinate-dehydrogenase-inhibiting (SDHI) fungicides boscalid and penthiopyrad was recently reported in the southern U.S. However, cross-resistance to the SDHI fungicide fluopyram has not yet been reported in this pathogen and isolates resistant to boscalid and penthiopyrad were confirmed as sensitive to fluopyram based on in vitro mycelial growth assays. In this study, baseline sensitivity to fluopyram was established using 98 isolates of D. bryoniae with no previous exposure to SDHI fungicides, using an in vitro mycelial growth assay on two different types of medium amended with fluopyram. The baseline will be used as a basis for establishing discriminatory concentrations for further resistance monitoring. Although yeast bactone acetate (YBA) medium has been recommended for SDHI sensitivity assays, based on our results, the mycelial growth assay using fungicide-amended potato dextrose agar medium was more reliable than YBA and produced more consistent results for determining sensitivity of this pathogen to fluopyram. >>>Impact: The baseline sensitivity of D. bryoniae to fluopyram will serve as a basis for establishing discriminatory concentrations for further resistance monitoring in this pathogen. >>>LIST OF RELEVANT PUBLICATIONS Avenot, H., Thomas, A., Gitaitis, R. D., Langston, D. B. Jr., and Stevenson, K. L. 2012. Molecular characterization of boscalid- and penthiopyrad-resistant isolates of Didymella bryoniae and assessment of their sensitivity to fluopyram. Pest Management Science 68:645651. Stevenson, K. L., Keinath, A. P., Thomas, A., Langston, D. B. Jr., Roberts, P. D., Hochmuth, R. C., and Thornton, A. C. 2012. Boscalid insensitivity documented in Didymella bryoniae isolated from watermelon in Florida and North Carolina. Plant Health Progress doi:10.1094/PHP-2012-0518-01-BR. Thomas, A., Langston, D. B. Jr., and Stevenson, K. L. 2012. Baseline sensitivity and cross-resistance within succinate-dehydrogenase-inhibiting fungicides and demethylation-inhibiting fungicides in Didymella bryoniae. Plant Dis. 96:979-984. Thomas, A., Langston, D. B. Jr., Sanders, H. F., and Stevenson, K. L. 2012. Relationship between fungicide sensitivity and control of gummy stem blight of watermelon under field conditions. Plant Disease (in press). ^^^^WERA-060 Annual Report for Michigan<<<< Mark E. Whalon, David Mota-Sanchez, Brittany Harrison and Rebeca Gutierrez. Department of Entomology. Michigan State University, East Lansing, MI48864 Report of the MSU Arthropod Pesticide Resistance Database and Resistance Pest Management Newsletter (WERA 60 Management of Pesticide Resistance) 2012 Mark E. Whalon, David Mota-Sanchez, Brittany Harrison and Rebeca Gutierrez. Department of Entomology. Michigan State University, East Lansing, MI48864 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, 597 species, 354 compounds, and 11,403 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. >> Impacts. Our database is visited frequently; recording about 58,000 page views 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. >>>Publications: Whalon, M.E., Mota-Sanchez, D. and Robert M. Hollingworth. 2013. Arthropod Pesticide Resistance Database 2013. On-line at: www.pesticideresistance.org This effort in reporting resistance was supported through a partnership between the Insecticide Resistance Action Committee (IRAC), USDA/CSREES/IPM, WERA 60, USDA and Michigan State University. >>>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 17 articles in 2012. The Bi-annual publication has over 1,150 electronic subscribers (mostly in government, industry and academia), and hard copies are now part of 60 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. >>>Publications: Resistant Pest Management Newsletter. 2012. A Biannual Newsletter of the Center for Integrated Plant Systems (CIPS) in Cooperation with the Insecticide Resistance Action Committee (IRAC) and the Western Regional Coordinating Committee (WRCC-60) Vol. 22, No. 1 (Fall 2012). On-line at: http://whalonlab.msu.edu/Newsletter/pdf/22_1.pdf ^^^^WERA-060 Annual Report for Montana<<<< William E. Dyer, Ph.D., Department of Plant Science and Plant Pathology, Telephone No.: (406) 994-5063), E-mail address: wdyer@montana.edu PROJECT TITLE: Physiological and Ecological Evaluation of Metabolism-Based Herbicide Resistance in Avena fatua (Wild Oat) >>>Overview: Significant progress was made on all objectives. Competitive funding in the amounts of $500,000 (USDA/NIFA) and $50,000 (Environmental Protection Agency Strategic Agricultural Initiative Program) was obtained to conduct this research. >>>Accomplishments: >>>Objective 1. Characterize the molecular regulation of multiple herbicide resistance in the A. fatua HRm biotype. The MHR wild oat biotypes MHR3 and MHR4 were derived from seeds collected in 2006 from two wild oat populations not controlled by 60 g a.i. ha-1 pinoxaden in two production fields separated by approximately 8 km in Teton County, Montana, USA. Herbicide susceptible biotype HS1 was derived from seeds of untreated plants in an adjacent field, and a second susceptible biotype HS2 is the nondormant inbred SH430 line used in seed dormancy research. Dose response experiments showed that the MHR biotypes are resistant to nine herbicides from five mechanism of action families, including three acetyl-CoA carboxylase (ACCase) inhibitors, three acetolactate synthase (ALS) inhibitors, the carbamothioate herbicide triallate, the membrane disruptor paraquat, and the growth inhibitor difenzoquat. Pre-treatment with the cytochrome P450 inhibitor malathion indicates that P450-mediated enhanced metabolism rates may be associated with resistance to flucarbazone (both MHR biotypes), imazamethabenz (MHR4), difenzoquat (MHR4), and pinoxaden (MHR3), but not for tralkoxydim, fenoxaprop-P, or triallate. DNA sequencing of the ACCase CT Domain and an ALS domain known to contain single nucleotide polymorphisms conferring herbicide resistance did not reveal any mutations associated with resistance in either MHR biotype. Polymerase chain reaction (PCR) using primers based on the O. sativa CYP81A6 sequence generated five unique but highly homologous (96-99% nucleotide identity) clones which shared 92-93% and 80-81% amino acid identity with the L. rigidum CYP81B1 and the O. sativa CYP81A6 cDNAs, respectively. In Northern hybridizations, the labelled 212-bp subfragment from AfCYP81L hybridized to a 1550-base band in RNA from HS and MHR biotypes. AfCYP81L mRNA levels were unchanged in HS1 and HS2 plants, but levels were consistently higher in MHR plants and increased in MHR3 plants after herbicide treatment. Thus, in both experiments using independent seedlots, AfCYP81L expression was constitutively higher in the MHR4 biotypes than the HS biotypes, and mRNA levels increased after herbicide treatment of MHR plants. Further, levels of AfCYP81L mRNA were induced to much higher levels than previously observed when HS1 and MHR4 plants were pre-treated with malathion before imazamethabenz treatment. Significantly, elevation of AfCYP81L mRNA levels in both HS and MHR plants indicates that malathion induces CYP gene expression in wild oat plants regardless of herbicide resistance phenotype. To our knowledge, this is the first report of malathion-induced CYP gene expression in any plant species. The qualitative differences between HS and MHR AfCYP81L expression levels we observed in Northern analyses were subsequently confirmed and quantified in qPCR assays. >>>Objective 2. Evaluate biological and environmental stressors determining fitness costs associated with enhanced herbicide metabolism in the A. fatua HRm biotype. We investigated two MHR wild oat (Avena fatua L.) populations from Montana, USA and hypothesized that they would exhibit fitness costs compared to two herbicide susceptible (HS) populations. This was accomplished in greenhouse studies, where we assessed differences between MHR and HS populations in seed germination, plant growth, and reproduction. We did not detect differences in seed germination rates across the four wild oat populations, and there were slight trends but no significant differences in relative growth rates at low or high nitrogen levels. Similarly we did not detect consistent differences in the ratio of root to shoot resource allocation among wild oat MHR and HS populations. Overall, our results do not indicate a consistent fitness cost, and thus generally do not strongly support expectations emerging from the resource-based allocation theory that MHR population should be less fit than HS populations. Greenhouse competition studies between wild oat and wheat plants did not reveal signficant differences in competitive ability of MHR or HS wild oats in the presence of wheat under several levels of nitrogen stress. As expected, wild oat biomass declined with increasing wheat biomass, although this relationship was minimal in the no nitrogen treatments where both wild oat and wheat biomasses were quite low compared to in the 50 and 100 kg N ha-1 treatments. The similar pattern observed with respect to wild oat RGR can also be attributed to the low wheat biomass in the unfertilized pots compared to fertilized ones. More importantly, there were no differences in the response of the HS and MRH populations to wheat competition or nitrogen stress, suggesting that there were no growth-related fitness costs for herbicide resistance. >>>Objective 3. Develop and deliver an extension program to educate producers and land managers about preventing and managing enhanced-metabolism herbicide resistance. Between 2010 and 2013, a total of 24 extension presentations on herbicide resistance prevention and management were delivered across Montana. These presentations directly reached an estimated audience of 928 attendants. Additionally, herbicide resistance was discussed at the 2011 Crops and Weeds Field Day in front of 65 farmers and agricultural professionals. We plan to present the results at the 2013 Crops and Weeds Field Day. >>>Impacts: These studies provide initial characterization of the MHR phenotype in wild oats. Resistance to multiple herbicides may be due in part to enhanced cytochrome P450-based metabolism, and we report the first example of a cytochrome P450 mRNA with elevated constitutive and inducible (by malathion and herbicide treatment) expression in any MHR biotype of any species. Our greenhouse studies do not support the presence of fitness costs associated with the MHR phenotype in wild oats, which is in conflict with the resource allocation theory. >>>Outputs: >>>Extension Bulletins Menalled, F. Weed management lessons from a dry and hot summer. Produced 8/21/2012. MSU IPM Bulletin. Menalled, F. Spring cropland weeds IPM, news and update. Produced 03/11/11. MSU IPM Bulletin. >>>Publications and Presentations in Professional Meetings Lehnhoff, E., B. K. Keith, W. E. Dyer, R. K. Peterson, and F. D. Menalled. In press. Characterization of multiple herbicide resistance in wild oat (Avena fatua) and its impacts on physiology, germinability, and seed production. Agronomy Journal. Lehnhoff, E. A., B. Keith, W. Dyer, and F.D. Menalled. In Press. Does multiple herbicide resistance modify crop-weed competitive interactions? Impact of biotic and abiotic stresses on multiple herbicide resistant wild oat (Avena fatua) in competition with wheat (Triticum aestivum). PLOS One. Keith, B., E. Lenhoff, E. Burns, F. Menalled, and W Dyer. In review. Elevated constitutive and inducible expression of a Cytochrome P450 mRNA in multiple herbicide resistant wild oat (Avena fatua L.). Mayes, E, Z. Miller, and F. Menalled. 2013. Is there a cost of herbicide resistance?: Effects of environmental and biological stressors on fitness of herbicide susceptible and multiple herbicide resistant Avena fatua L. (wild oat) biotypes. Western Society of Weed Science Meeting. March 11-14, 2013. San Diego, CA. Lehnhoff, E., F. Menalled, B. Keith, and W. Dyer. 2012. Fitness costs of multiple herbicide resistant wild oat. Western Society of Weed 65th Annual Meeting. March 12-15, 2012. Reno, Nevada Miles, G., E. Kalinina, and W.E. Dyer. 2011. Investigation of multiple herbicide resistance in Avena fatua L. Montana State University Undergraduate Scholars Conference, March, 2011. Boyd, M., B. Keith, and W.E. Dyer. 2012. Are glutathione S-transferases involved in multiple herbicide resistance in Avena fatua? Montana State University Undergraduate Scholars Conference, March, 2012. Davis, E.S., W.E. Dyer, and F. Menalled. 2013. Herbicide Resistant Wild Oat Occurrence in Diverse Cropping Systems: Two Case Studies. Proc. West. Soc. Weed Sci. 66:nnn. ^^^^WERA-060 Annual Report for Nebraska<<<< B.D. Siegfried, Department of Entomology, University of Nebraska, Lincoln, NE Lincoln, NE68583-0816 bsiegfried1@unl.edu, Voice: 402-472-8714 >>>Rangasamy, M. and. 2012. Validation of RNA interference in western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) adults. Pest Manag. Sci. 68: 587-591. BACKGROUND: RNA interference (RNAi) is commonly used in insect functional genomics studies and usually involves direct injection of double-stranded RNA (dsRNA). Only a few studies have involved exposure to dsRNAs through feeding. For western corn rootworm (Diabrotica virgifera virgifera) larvae, ingestion of dsRNA designed from the housekeeping gene, vacuolar ATPase (vATPase) triggers RNAi causing growth inhibition and mortality; however, the effect of dsRNA feeding on adults has not been examined. In this research, WCR adults were fed with vATPase-dsRNA-treated artificial diet containing a cucurbitacin bait, which is a proven feeding stimulant for chrysomelid beetles of the subtribe Diabroticina to which rootworms belong. RESULTS: Real-time PCR confirmed suppression of vATPase expression and western blot analysis indicated reduced signal of a protein that cross-reacted with a vATPase polyclonal antiserum in WCR adults exposed to artificial diet treated with dsRNA and cucurbitacin bait. Continuous feeding on cucurbitacin and dsRNA-treated artificial diet resulted in more than 95% adult mortality within 2 weeks while mortality in control treatments never exceeded 20%. CONCLUSIONS: This research clearly demonstrates the effect of RNAi on WCR adults that have been exposed to dsRNA by feeding and establishes a tool to screen dsRNAs of potential target genes in adults. This technique may serve as an alternative to target screening of larvae which are difficult to maintain on artificial diets. >>>Chen, H., H. Wang, and B.D. Siegfried. 2012. Genetic differentiation of western corn rootworm populations (Coleoptera: Chrysomelidae) with resistance to insecticides. Ann. Entomol. Soc. Am. 105: 232-240. As the single most important pest of field corn, Zea mays L., throughout most of the Corn Belt, the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), has undergone repeated selection for resistance to a variety of insecticides that persist widely among Nebraska populations. In this study, we used 11 microsatellite markers to genotype two populations with high levels of resistance to methyl-parathion and aldrin (Polk and Stromsburg), two populations with low and intermediate levels of resistance (Mead and Clay Center) from Nebraska, and one population from outside the Corn Belt (Safford, AZ). The genetic diversity measured by observed heterozygosity (H0) was reduced 1532% in the highly resistant populations compared with the more susceptible populations in Nebraska. Significant genetic differentiation was detected between the resistant and susceptible populations (Polk and Stromsburg versus Mead and Clay Center) in Nebraska (FST = 0.016) and between all the populations from Nebraska and Arizona (FST = 0.059). The average observed heterozygosities in the populations were positively correlated with insecticide susceptibility based on mortality at diagnostic concentrations of aldrin and methyl-parathion, respectively. These results indicate that the insecticide selection from exposure to aldrin and methyl-parathion may be a contributing factor in shaping the genetic structure of western corn rootworm populations in Nebraska. Factors including isolation by distance and a Wolbachia-induced breeding barrier may have contributed to differentiation of rootworm populations from Nebraska and Arizona. >>>Coates, B.S., A. Alves, H. Wang, K. Walden, B. W. French, N.J. Miller, C.A. Abel, H.M. Robertson, T.W. Sappington, and B.D. Siegfried. 2012. Distributions of genes and repetitive elements in Diabrotica virgifera virgifera: prelude to assembling a large, repetitive genome. J. Biomed. Biotechnol. doi:10.1155/2012/604076. Abstract: Feeding damage caused by the western corn rootworm, Diabrotica virgifera virgifera, is destructive to corn plants in North America and Europe where control remains challenging due to evolution of resistance to chemical and transgenic toxins. A BAC library, DvvBAC1, containing 109,486 clones with 104 ± 34.5 kb inserts was created, which has an ~4.56X genome coverage based upon a 2.58 Gb (2.80 pg) flow cytometry-estimated haploid genome size. Paired end sequencing of 1037 BAC inserts produced 1.17 Mb of data (~0.05% genome coverage) and indicated ~9.4 and 16.0% of reads encode, respectively, endogenous genes and transposable elements (TEs). Sequencing genes within BAC full inserts demonstrated that TE densities are high within intergenic and intron regions and contribute to the increased gene size. Comparison of homologous genome regions cloned within different BAC clones indicated that TE movement may cause haplotype variation within the inbred strain. The data presented here indicate that the D. virgifera virgifera genome is large in size and contains a high proportion of repetitive sequence. These BAC sequencing methods that are applicable for characterization of genomes prior to sequencing may likely be valuable resources for genome annotation as well as scaffolding. >>>Siegfried, B.D. and R.L. Hellmich. 2012. Understanding successful resistance management: The European corn borer and Bt corn in the United States. Special Issue of GM Crops and Foods 3: 184-193. Abstract: The European corn borer, Ostrinia nubilalis Hübner (Lepidoptera: Crambidae) has been a major pest of corn and other crops in North America since its accidental introduction nearly a hundred years ago. Wide adoption of transgenic corn hybrids that express toxins from Bacillus thuringiensis, referred to as Bt corn, has suppressed corn borer populations and reduced the pest status of this insect in parts of the Corn Belt. Continued suppression of this pest, however, will depend on managing potential resistance to Bt corn, currently through the high-dose refuge (HDR) strategy. In this review, we describe what has been learned with regard to O. nubilalis resistance to Bt toxins either through laboratory selection experiments or isolation of resistance from field populations. We also describe the essential components of the HDR strategy as they relate to O. nubilalis biology and ecology. Additionally, recent developments in insect resistance management (IRM) specific to O. nubilalis that may affect the continued sustainability of this technology are considered. ^^^^WERA-060 Annual Report for 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 7th edition of the Fungicide Resistance Management Guidelines for Vegetable Crop Production in the mid-Atlantic Region was published in 2012. Since 2007, over 15,000 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. Publications: none ^^^^WERA-060 Annual Report for New York (Long Island)<<<< Margaret Tuttle McGrath, Long Island Horticultural Research & Extension Center, Riverhead, NY 11901-1098, (631) 727-3595, Email: mtm3@cornell.edu >>>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 wind dispersed long distances enabling widespread dispersal of resistant strains. Sensitivity to fungicides was examined for 55 pathogen isolates collected at the end of the 2011 growing season from commercial and research cucurbit fields. A leaf disk bioassay was used. Resistance to QoI fungicides (FRAC code 11) was detected in 79% of the isolates tested (not all isolates were tested with this fungicide). Resistance to this fungicide chemistry is qualitative, thus pathogen isolates are either sensitive or resistant, and fungicides are ineffective against resistant isolates. There is a fungicide (Pristine) with a FRAC code 11 active ingredient that has continued to be recommended because it contains another active ingredient (FRAC code 7). Applying Pristine could select for pathogen strains resistant to FRAC code 11 fungicides, thereby maintaining this resistance in the pathogen population. Resistance to most fungicide chemistry is quantitative, including active ingredients in Pristine, Procure, Rally, and Quintec. With this type of resistance, pathogen isolates exhibit a range in sensitivity. Several concentrations are used in assays to characterize sensitivity. Ability to grow on leaf disks with a high concentration (500 ppm) of boscalid, an active ingredient in Pristine, was detected in only 6% of the pathogen isolates tested. This concentration is in the range of what would be in the spray tank when Pristine is applied at labeled rates, therefore isolates tolerating 500 ppm are likely fully resistant to this fungicide, which means they would not be controlled by Pristine. Each of the three isolates were obtained from a different farm. In contrast, 43% of the isolates collected in 2010 from similar locations were resistant. With myclobutanil, the active ingredient in Rally, a DMI (FRAC code 3) fungicide, 4% of isolates tolerated 80 ppm, 33% tolerated 40 ppm, while 16% were sensitive to 10 ppm. The concentration in the spray tank would be 150 ppm for Rally applied at the lowest label rate (2.5 oz/A) and 50 gpa. With quinoxyfen, the active ingredient in Quintec (FRAC code 13) fungicide, 4% of isolates tolerated 80 ppm, 24% tolerated 40 ppm, while 22% were sensitive to 10 ppm. The concentration in the spray tank would be 141 ppm for Quintec applied at the lowest label rate (4 fl oz/A) and 50 gpa. One of the two isolates able to tolerate 80 ppm quinoxyfen was also resistant to boscalid Sensitivity to Topsin M was examined for some isolates to determine if the pathogen is maintaining resistance to this old fungicide. It was found that resistance continues to be common to this fungicide group (MBC; FRAC code 1); however, there were fewer resistant isolates in 2011 (50%) than in previous years when most isolates were resistant (97% in 2010). Efficacy of fungicides at-risk for resistance was assessed in a replicated experiment conducted in 2012 with products applied individually to pumpkins using a tractor-sprayer. These results in comparison with those from experiments in previous years provides some indication when the pathogen might be developing resistance. Among currently registered fungicides, Pristine (FRAC Code 7 and 11) applied at its highest label rate was ineffective. In previous years at this location, pathogen isolates resistant to both components of this fungicide have been detected, and the fungicide has exhibited variable performance in previous evaluations. Powdery mildew also was not effectively controlled by Fontelis (FRAC 7), a chemically-related fungicide registered in 2012. Procure (FRAC 3) applied at its highest label rate was effective through 28 August on both leaf surfaces. Quintec (FRAC 13) was highly effective through the last assessment on 6 Sep when the other registered fungicides were no longer effective. A seedling bioassay was conducted in research fields early in the 2012 season to obtain estimates of the proportion of the pathogen population able to tolerate fungicides at the concentrations applied to the seedlings. Strains of the pathogen were detected able to tolerate 500 ppm boscalid (active ingredient in Pristine), 120 ppm myclobutanil (Rally) and 10 ppm quinoxyfen (Quintec). Ability to tolerate 500 ppm boscalid is of concern because this concentration is in the range of what would be in the spray tank when Pristine is applied. Resistance is common to the other active ingredient in Pristine, which is in FRAC code 11. Therefore Pristine would not be expected to be able to control these strains. On average, a lower proportion of the pathogen populations were able to tolerate 10 ppm quinoxyfen than 500 ppm boscalid. Therefore Quintec was expected to be the most effective fungicide in 2012. Quintec was very effective while Pristine was ineffective in the fungicide efficacy experiment. >>>2012 Publications McGrath, M. T., and Hunsberger, L. K. 2012. Efficacy of fungicides for managing cucurbit powdery mildew and pathogen sensitivity to fungicides, 2011. Plant Disease Management Reports 6:V080. ^^^^WERA-060 Annual Report for New York (Ithaca)<<<< Jeff Scott, Cornell University Agricultural Experiment Station, Ithaca, NY 14853-5905 >>> Accomplishments We investigated the population genetics of target site resistance to pyrethroid insecticides in house flies and Colorado potato beetles. We found that for both species there were multiple evolutionary origins of kdr (Vssc mutation L1014F). In addition, house flies have super-kdr and kdr-his alleles. These alleles also have multiple evolutionary origins, although super-kdr appears to evolve only in flies that already have the kdr mutation. >>> Impacts Pyrethroid insecticides continue to be widely used, but the evolution of resistance is reducing their effectiveness in many locations (against many species). Our finding of multiple evolutionary origins for resistance mutations in Vssc indicate resistance management must focus on a relatively localized resistance management plan, as immigration is not necessary for this type of resistance to appear in a population. >>> Publications relevant to this project, since the last report. Rinkevich, F. D., Hedtke, S. M., Leichter, C. A., Harris, S. A., Su, C., Brady. S. G., Taskin, V., Qiu, X. and Scott, J. G. 2012. Multiple origins of kdr-type resistance in the house fly, Musca domestica. PLOS One 7:e52761. Rinkevich, F. D., Su, C., Lazo, T. A., Hawthorne, D. J., Tingey, W. M., Naimov, S. and Scott, J. G. 2012. Multiple evolutionary origins of knockdown resistance (kdr) in pyrethroid-resistant Colorado potato beetle, Leptinotarsa decemlineata. Pestic. Biochem Physiol. 104: 192-200. Wang, Q., Li, M., Pan, J., Di, M., Liu, Q., Meng, F., Scott, J. G. and Qui, X. 2012. Diversity and frequencies of genetic mutations involved in insecticide resistance in field populations of the house fly (Musca domestica L.) from China. Pestic. Biochem. Physiol. 102: 153-159.

Publications

[Please see attached pdf file.]

Publications Attachment:

Attachment

Impact Statements

Information focused on applied research and extension to enhance pesticide resistance management was exchanged across disciplines, geographic regions, and systems. Members gained unique perspectives to guide their individual research, extension, and teaching efforts.
Through a variety of means, information on pesticide resistance and resistance management reached important audiences and stakeholders in the scientific community, in industry, and among regulators.
Specifically, publication of the Arthropod Pesticide Resistance Database (APRD), provided a resource used both by USEPA, EU and industry (IRAC International) authorities as well as pest managers in the US and internationally for resistance reporting for pesticide registration and pesticide reregistration processes as well as recommendations in resistance management.

Date of Annual Report: 05/12/2015

Report Information

Annual Meeting Dates: 02/02/2014 - 02/03/2014
Period the Report Covers: 10/01/2013 - 09/01/2014

Participants

Todd Gaines;
Mike Marshall;
Mike Owen;
Carol Mallory-Smith;
Meg McGrath;
Bob Nichols;
Bill Vencill;
Phil Westra;

Brief Summary of Minutes

Please see attached file.

Minutes Attachment:

Attachment

Accomplishments

>>>Resistance Definitions A major portion of WERA060 effort has been devoted to developing and reviewing “Resistance Definitions” that can be applied to insecticides, miticides, fungicides, and herbicides. The following draft was prepared: -A- acquired resistance – Resistance to a pesticide in a population acquired through the long-term exposure of the pest to sub-lethal doses over multiple pest generations. altered target-site resistance – Tolerance to a pesticide due to a genetic change leading to an alteration in the target enzyme, protein, or molecule that leads to reduced or no binding of the pesticide. artificially-induced resistance – The development of resistance to a pesticide caused by the deliberate exposure of the pest to sub-lethal doses of a pesticide. -B- baseline sensitivity – A profile of the fungicide sensitivity of a target fungal population based on biological or molecular techniques to assess the response of previously unexposed individual populations to the fungicide of interest. behavioral resistance – Reduced effectiveness of pesticides caused by behavioral changes in a insect pest such as avoidance of pesticide treated hosts; not a result of direct biochemical changes of the organism to the pesticide at the cellular level. biotype – An individual or group of individuals within a particular species having biological traits that are not common to the population as a whole. -C- continuous resistance – The establishment of stable pest populations that are biochemically resistant to a pesticide. This may also refer to the pattern of resistance development in populations where a continuous, quantitative range of sensitivity values can be detected. See directional resistance, quantitative resistance. correlated-resistance – Individuals resistant to one type of pesticide are also resistant to another pesticide with a different biochemical mode of action or target site. See also multiple resistance. cross-resistance – Resistance to multiple pesticides that share the same biochemical mode of action or target site. -D- detoxification mechanisms – A process or processes by which a fungicide is detoxified before the active ingredient reaches the target site. Several different biochemical mechanisms may occur which result in the fungicide being detoxified. The biochemical mechanisms can generally be classified as either: conjugation, hydroloysis, oxidation, or reduction. This can also be referred to as metabolism, see metabolic resistance. directional resistance –A unimodal pattern of resistance development where selection within a population with a continuous, quantitative range in pesticide sensitivity results in an increased frequency of individuals with lower pesticide sensitivity (e.g. the population distribution shifts directionally towards a higher frequency of less sensitive individuals, but the distribution remains a continuous range of pesticide sensitivity). Typically, increased rates of a specific pesticide or using a pesticide with higher inherent activity can provide some control of the population under field conditions. See also continuous resistance, quantitative resistance. discontinuous resistance – A bimodal pattern of resistance development where selection of a population results in the increased frequency of individuals greatly insensitive to the pesticide, usually caused by a target site mutation. See also qualitative resistance, discrete resistance, disruptive resistance. discrete resistance – See qualitative resistance. disruptive resistance – See qualitative resistance. -E- efflux mechanisms – Specific to antibiotic resistance mechanisms within bacterial cells. A method responsible for toxin or antibiotic extrusion outside of a bacterial cell. See intrinsic or acquired resistance. -F- field resistance – A situation where the frequency of resistant individuals in a given pest population is high enough (due to repeated selection events) so that the effectiveness of the pesticide application is compromised such that decreased control is noticed in the field. See also practical resistance. field-evolved resistance – Resistance development in pests in response to field applications of pesticide(s) where repeated use results in the selection of naturally-tolerant individuals to a frequency where control with pesticide(s) is compromised. See practical resistance. fitness – The ability of a pest to naturally reproduce. A pest is often described as having a loss of fitness, or reduced, or increased fitness in the presence of a certain selection pressure, often the presence or absence of a pesticide. forma specialis (f.sp.) – a subspecies or group of strains within a fungal species that can only infect plants within a particular (range of) species, e.g., Puccinia graminis f.sp. tritici. -H- haplotype – A set of DNA polymorphisms, or variations, that tend to be inherited together from a single parent. heteroplasmy – The presence of more than one mitochondrial DNA (mtDNA) within a cell whereby some mutant DNA and wild type DNA is present within the single cell. hormoligosis – The effect of stimulating pest activity through exposure to sub-lethal doses of pesticides; may also be related to the stimulation of pest activity from non-target effects (i.e. increasing pathogen activity with insecticide applications). -I- immunity – Describes a situation where an individual has a mutation that causes the target site to no longer bind to the pesticide, or at such a low level that commercially useable doses of pesticides are ineffective for control. insensitivity – The development of biochemical immunity to a pesticide. See resistance. intrinsic activity – The inhibitory activity of a fungicide against a given species of plant pathogens, based on its ability to bind to the target and to confer growth inhibition, independent of environmental factors that affect its activity, and of the possibility of the selection of individuals that have developed resistance against the fungicide. isolate – A pure culture of a particular organism such as a fungus. Often requires single spore isolation or bacterial colonies from a single cell to have as much genetic homogeneity as possible. -L- laboratory resistance – Selection of resistant pests through repeated pesticide exposure under controlled conditions. This may entail using mutagens to create mutants followed by selection using pesticides. Resistant pests created in this manner may or may not reflect genetic mutations that would survive under natural conditions. The term laboratory resistance is also used to describe resistance phenotypes of field strains that have been described in laboratory assays. Depending on their degree of resistance and their frequency in the field, strains with laboratory resistance might or might not result in field resistance of the fungal population. low-level resistance – The development of tolerance to low doses of a pesticide that may not be significant relative to the rates or doses of pesticides used for commercial pest control. -M- major gene resistance – Resistance associated with changes to a single gene. With known cases the gene affects the pesticide binding ability to the target molecule, protein or enzyme. Typically associated with a target site mutation that confers resistance to the pesticide. major resistance – Pest resistance associated with high economic or biological impact. mechanism of action – See mode of action. mechanism of resistance – The process by which a pest become biochemically resistant to pesticide. Processes are typically related to target site mutations, decreased binding to the target a site, increased gene expression, detoxification or degradation of the pesticide, or efflux of the pesticide away from the target site. This may also refer to the selection process for pest populations and the patterns of increased frequencies of resistant individuals in response to pesticide use strategies. metabolic resistance – Biochemical resistance development based on detoxification or degradation of the pesticide, or efflux of the pesticide away from the target site; e.g. where the target site remains susceptible to pesticide binding but where binding of the pesticide to the target is reduced by other cellular processes. mixed function oxidases – insect enzymes involved in metabolizing insecticides thereby imparting resistance to the pest. mode of action – The biological process by which a pesticide specifically inhibits (biochemical mode of action) the development of a given pest. For example, the biochemical mode of action of QoIs is through the inhibition of cellular respiration. See also target site of action, which describes the exact location of a molecule where a pesticide binds. This may also describe the temporal and spatial characteristics of a pesticide in inhibiting the life or infection cycle of a pest (physical mode of action). For example, QoIs are strongest at inhibiting spore germination and infection processes and have a “protectant” mode of action. multidrug resistance (MDR) – A resistance mechanism based on increased drug efflux, leading to simultaneously reduced sensitivity against several fungicides. Widely observed in European Botrytis cinerea populations from fungicide-treated vineyards and small fruit fields. The major MDR type, MDR1, leads to reduced sensitivity to fludioxonil and anilinopyrimidines, due to mutations in the transcription factor Mrr1 that lead to overexpression of the ABC transporter encoding gene, atrB. MDR2 is caused by overexpression of the MfsM2 transporter triggered by promoter rearrangements, and confers reduced sensitivity to fenhexamid, anilinopyrimidines and iprodione. MDR3 refers to strains expressing both MDR1 and MDR2. Recently, MDR-related mechanisms have been shown to contribute to azole resistance in Mycosphaerella graminicola. multi-step resistance – This refers to the pattern of selection in a population with a continuous distribution of sensitivities to a given pesticide, and when resistance to the same fungicide class is conferred by more than one target site mutation or genetic mechanism. Each of the mutations or mechanisms gives an additive effect. Individuals with a single or a few mutations may have a moderately tolerant phenotype, and those with multiple mutations or mechanisms may have a highly tolerant phenotype. This may also be referred to as “multigenic” resistance. Repeated applications of the pesticide selects for increasingly tolerant individuals and is dependent on the dose of pesticide used, e.g. low doses select out the most sensitive individuals within the population allowing for the survival of moderately sensitive individuals whereas higher doses select out low and moderately sensitive individuals. Very high doses may have a neutral overall effect on the pest, as the dose is so high that even the least sensitive individuals are still controlled. DMI fungicide resistance is a good example of this phenomenon. See also qualitative resistance, and quantitative resistance. multiple resistance – Biochemical resistance development to two or more unrelated pesticide classes. This may result from selection of individuals naturally resistant to two or more pesticides or the sequential selection of individuals resistant to one pesticide class which then naturally obtain a mutation conferring resistance to another pesticide and are subsequently selected for by the use of the latter pesticide. -N- negative cross-resistance – A situation where a pesticide only affects individuals resistant to another class of pesticides. An example is the N-phenylanilines, which are only toxic to individuals that are benzimidazole resistant and ineffective against benzimidazole sensitive individuals. Note that multiple resistance can develop to both pesticides, such in the previous case where an adjacent target site mutation in beta-tubulin also confers resistance to N-phenylanilines in benzimidazole resistant individuals. -O- overexpression – Excessive expression of a particular gene by producing too much of its product or effect. This can lead to a reduction in sensitivity to fungicides in specific fungal systems (e.g., Blumeria jaapii, Fusarium graminearum, Monilinia fructicola, Penicillium digitatum, Sclerotinia homoeocarpa) and a reduction in sensitivity to antibiotics in specific bacterial systems. -P- partial cross-resistance – A situation where biochemical resistance to one pesticide also confers low levels of resistance or tolerance to another pesticide class with a different biochemical mode of action. pathotype – A classification of a pathogen that is distinguished from others within a given species based on its pathogenicity to specific host(s). pathovar (pv.) – A subspecies or group of strains within a bacterial species that can only infect plants within a particular species, e.g., Pseudomonase syringae pv. tomato. pathosystem – A host plant species along with the parasites (bacteria, fungi, virus) that utilize the host plant. penetration resistance – Resistance associated with the selection of traits that inhibit the pesticide’s ability to reach the target site in the pest. Most commonly associated with insecticides and the selection of insects for cuticles that are less susceptible to insecticide absorbance and penetration. practical resistance – The situation where the frequency of biochemically resistant individuals in a population reaches a point at which field or commercial pesticide applications no longer provide aesthetically or economically acceptable control. This is a relative term as “acceptable levels of control” amongst crops can be variable depending on the use or value of the crop. progressive resistance – See multi-step resistance and quantitative resistance. -Q- qualitative resistance – A pattern of resistance development in populations where there is a distinct separation between sensitive and resistant individuals. Individuals are either sensitive to the pesticide or resistant to levels of the pesticide that could be feasibly used. This is typically associated with target site mutations that confer immunity to a pesticide for an individual. quantitative resistance – A pattern of resistance development in populations where there is a continuous range of sensitivity amongst individuals in a population. Individuals may have increased tolerance to a pesticide, but generally, increased doses are still be toxic. This is typically associated with target site mutations, metabolic resistance mechanisms or other genetic changes that confer tolerance but not immunity to a pesticide. -R- reduced sensitivity – Over time the population develops the ability to overcome the pesticide used and the population present evolves strains that no longer are susceptible/sensitive to an appropriate rate of pesticide. reduced uptake – The fungicide is absorbed at a much slower rate by the resistant fungus than the susceptible type (wild-type). removal – A fungal cell exports the fungicide rapidly before the chemical reaches the target site of action. resistance – Decreased sensitivity of a pest to a pesticide that results in immunity or tolerance to the pesticide; resistance must be a heritable trait with a genetic basis. resistance risk – Likelihood of resistance developing to a pesticide or within a pest population. resistance ratio – The ratio of resistant individuals relative to sensitive (wild-type) individuals in a population. This may also refer to the difference between mean population sensitivities (typically expressed as 50% effective dose (ED50) values) when populations exhibit a quantitative pattern of resistance development. resurgence – The situation where the application of a pesticide to a population containing resistance to the pesticide causes an increase in this pest’s damage or activity. This may be due to the negative affect of the pesticide on other competing pests or organisms but essentially no effect on the resistant individuals, putting them at an ecological advantage. Resurgence is also used in situations where the pesticide has not been used for awhile in an effort to revert the pathogen population to sensitive individuals. -S- single-step resistance – Resistance conferred by a single mechanism of resistance such as a single target site mutation or single metabolic change. This may also be referred to as “monogenic” resistance. See also qualitative resistance. site-specific mode-of-action – See mode of action. strain – A variant of a particular organism. sustained susceptibility – The situation where either a pest has failed to develop resistance to a pesticide despite repeated use due to biological or behavioral reasons, or a situation where biochemically resistant individuals are present but are maintained at a low level, thus practical resistance never develops. -T- target site of action – The physical site of interaction between a pesticide and the pest. For single site of action pesticides, this is a specific enzyme, protein, or molecule involved in a key biological process. For example, QoIs bind specifically to the Qo-site of cytochrome bc1. See also mode of action, which describes the biological process inhibited by the pesticide. tolerance – Reduced sensitivity of an individual pest to a pesticide conferred by genetic changes relative to a wild-type individual. Tolerant individuals may be affected by higher doses of the pesticide. -V- variant – A different genotype present within a population, such as a genotype adapted to be resistant to a pesticide. -W- wild-type population – The genotypes in a population before exposure to a pesticide or another change in the environment that results in adaptation in the pathogen. >>>>>Potential New Members and Recruiting A list of 10 new members from the discipline of plant pathology was developed and a plan discussed in an effort to increase plant pathology involvement. >>>>>Draft Webinar Development The main goal is to cover resistance terminology across the three disciplines (weed science, entomology and plant pathology). EPA staff had voiced a need for understanding and harmonization of definitions of resistance terminology across the disciplines. There is need to determine what other goals EPA has for the webinar to ensure we meet their needs. Audience for the webinar was discussed. EPA staff is the main audience. APHIS staff and legislators are also important to target. A key to success of the webinar will be working with people in each of our societies who have formal connections in DC including with EPA. >>>>>State Specific Accomplishments **Colorado Herbicide Resistant Kochia in Colorado Todd Gaines, Eric Westra, Scott Nissen, and Philip Westra Department of Bioagricultural Sciences and Pest Management Colorado State University As herbicides continue to be an essential tool for weed control, ongoing herbicide sustainability is essential in Colorado cropping systems. Research projects pertaining to the evolution and management of resistance in important species including kochia, Palmer amaranth, waterhemp, giant ragweed, and barnyardgrass are ongoing in the CSU weed science program. Several Colorado kochia samples collected in 2011 showed glyphosate resistance when tested in glyphosate dose response studies in the CSU weed science greenhouse. Some individual plants survived up to 1.25 gallons of glyphosate, although the general level of increased resistance appears to be in the 3-6 fold range. Glyphosate-resistant kochia in Colorado contains extra copies of the gene EPSPS, which encodes the protein inhibited by glyphosate. The resistant plants produce enough extra enzyme to survive normal glyphosate applications. Glyphosate-resistant kochia sampled from Colorado usually has from 4 to 10 extra copies of the EPSPS gene. We have sampled glyphosate-resistant kochia from other states and Canada, and some samples are more resistant and have 15 or more copies of the EPSPS gene. This indicates that higher resistance levels can be selected if diversity is not incorporated into kochia management programs. The CSU weed science program is conducting surveys to understand the distribution of glyphosate-resistant kochia in CO and numerous studies to look for other herbicides that can be used to control this resistant kochia. We have conducted surveys to test for glyphosate and dicamba resistance in kochia from eastern CO in 2011, 2012, and 2013. In 2011, 10% of kochia samples were classified as glyphosate resistant (defined as when >20% of tested individuals from a sample are deemed resistant). In 2012, 24% of kochia samples were classified as glyphosate resistant, and in 2013, 12% of kochia samples were glyphosate resistant. For dicamba, 11% of samples in 2012 and 9% of samples in 2013 were classified as dicamba resistant. For both glyphosate and dicamba, the samples usually contain both resistant and susceptible individuals. Importantly, some samples were resistant to both glyphosate and dicamba. Both dicamba and glyphosate are important tools for weed management in no-till and reduced tillage cropping systems. The occurrence of glyphosate-resistant and dicamba-resistant kochia populations highlights the need to incorporate diversity into weed management practices, and to take efforts to remove surviving individuals from fallow fields before they can set seed and potentially spread resistance. **Michigan Mark Whalon Maintained and updated the Arthropod Pesticide Resistance Database http://www.pesticideresistance.com/ Focused attention on the Maximum Residue Limit (MRL) issues, critical to Upper Midwest tree fruit and small fruit export/import agreements. ** South Carolina Mike Marshall Documented resistance to multiple herbicides in two weed species. Palmer amaranth (group 9, group 2 and group 3 herbicides). Italian ryegrass (group 1 and group 2 herbicides).

Publications

Coates B. S., D. V. Sumerford, B. D. Siegfried, R. L. Hellmich, C. A. Abel. 2013. Unlinked genetic loci control the reduced transcription of aminopeptidase N 1 and 3 in the European corn borer and determine tolerance to Bacillus thuringiensis Cry1Ab toxin. Insect biochemistry and molecular biology 43:1152-1160. Enders, LS, Ryan D Bickel, Jennifer A Brisson, Tiffany M Heng-Moss, Blair D Siegfried, Anthony J Zera, Nicholas J Miller. 2014. Genes Genomes Genetics 5(2). DOI:10.1534/g3.114.015149. Martins B. A., E. Sánchez-Olguín, A. Perez-Jones, A. G. Hulting, and C. Mallory-Smith. 2014. Alleles contributing to ACCase-resistance in an Italian ryegrass (Lolium perenne ssp. multiflorum) population from Oregon. Weed Sci. 62:468-473. Enders, Laramy S., Ryan D Bickel, Jennifer A Brisson, Tiffany M Heng-Moss, Blair D Siegfried, Anthony J Zera, Nicholas J Miller. 2014. Abiotic and Biotic Stressors Causing Equivalent Mortality Induce Highly Variable Transcriptional Responses in the Soybean Aphid. Genes Genomes Genetics 12/2014; 5(2). DOI:10.1534/g3.114.015149. Eyun, Seong-Il , Haichuan Wang, Yannick Pauchet, Richard H Ffrench-Constant, Andrew K Benson, Arnubio Valencia-Jiménez, Etsuko N Moriyama, Blair D Siegfried. 2014. Molecular Evolution of Glycoside Hydrolase Genes in the Western Corn Rootworm (Diabrotica virgifera virgifera). PLoS ONE 04/2014; DOI:10.1371/journal.pone.0094052. Giacomini D., P. Westra, and S. M. Ward. 2014. Impact of genetic background in fitness cost studies: An example from glyphosate-resistant Palmer amaranth. Weed Sci. 62:29-37. Gökçe, A., L.L. Stelinski; D.R. Nortman; W.W. Bryan; M.E. Whalon. 2014. Behavioral and electroantennogram responses of plum curculio, Conotrachelus nenuphar, to selected noxious plant extracts and insecticides. Journal of Insect Science.? 14:90. Kirsch, Roy, Lydia Gramzow, Günter Theißen, Blair D. Siegfried, Richard H. ffrench- Constant, David G. Heckel, Yannick Pauchet. 2014. Horizontal Gene Transfer and Functional Diversification of Plant Cell Wall Degrading Polygalacturonases: Key Events in the Evolution of Herbivory in Beetles. Insect Biochemistry and Molecular Biology 06/2014; 52:33-50. DOI:10.1016/j.ibmb.2014.06.008. Lorentz L., T. A. Gaines, S. J. Nissen, P. Westra, H. Strek, H. W. Dehne, J. P. Ruiz-Santaella, and R. Beffa. 2014. Characterization of glyphosate resistance in Amaranthus tuberculatus populations. J. Agric. Food Chem. 62:8134-8142. McGrath, M. T., & LaMarsh, K. A. 2014. Evaluation of biopesticides for managing foliar diseases in organically-produced tomato, 2013. Plant Disease Management Reports. 8:V194. McGrath, M. T., & LaMarsh, K. A. 2014. Efficacy of fungicides for managing downy mildew in cucumber, 2013. Plant Disease Management Reports. 8:V192. McGrath, M. T., & LaMarsh, K. A. 2014. Efficacy of fungicides for managing powdery mildew in pumpkin, 2013. Plant Disease Management Reports. 8:V204. Mingyang Liu, Andrew G Hulting, Carol Mallory-Smith. 2014. Characterization of Multiple Herbicide-Resistant Italian Ryegrass (Lolium Perenne spp. Multiflorum). Pest Management Science 70(7). DOI: 10.1002/ps.3665. Petzold-Maxwell, Jennifer L., Blair D Siegfried, Richard L Hellmich, Craig A Abel, Brad S Coates, Terrence A Spencer, Aaron J Gassmann. 2014. Effect of Maize Lines on Larval Fitness Costs of Cry1F Resistance in the European Corn Borer (Lepidoptera: Crambidae). Journal of Economic Entomology 04/2014; 107(2):764-72. DOI:10.1603/EC13359. Pyne, RM, AR Koroch, CA Wyenandt, JE Simon. 2014. A Rapid Screening Approach to Identify Resistance to Basil Downy Mildew (Peronospora belbahrii). HortScience 49 (8), 1041-1045. Sammons D. R., and T. A. Gaines. 2014. Glyphosate resistance: State of knowledge. Pest Manag. Sci. 70:1367-1377. Siegfried, Blair D., Murugesan Rangasamy, Haichuan Wang, Terence Spencer, Chirakkal V Haridas, Brigitte Tenhumberg, Douglas V Sumerford, Nicholas P Storer. 2014. Estimating the Frequency of Cry1F Resistance in Field Populations of the European Corn Borer (Lepidoptera: Crambidae). Pest Management Science 05/2014; 70(5). DOI:10.1002/ps.3662. Stamm, Mitchell D., Laramy S Enders, Teresa J Donze-Reiner, Frederick P Baxendale, Blair D Siegfried, Tiffany M Heng-Moss. 2014. Transcriptional response of soybean to thiamethoxam seed treatment in the presence and absence of drought stress. BMC Genomics 12/2014; 15(1):1055. DOI:10.1186/1471-2164-15-1055. Tabashnik, Bruce E., David Mota-Sanchez, Mark E. Whalon, Robert M. Hollingworth, Yves Carrière. 2014. Defining terms for proactive management of resistance to Bt crops and pesticides. Journal of Economic Entomology.?107(2):496-507. Wiersma A. T., T. A. Gaines, C. Preston, J. P. Hamilton, D. Giacomini, C. R. Buell, J. E. Leach, and P. Westra. 2015. Gene amplification of 5-enol-pyruvylshikimate-3-phosphate synthase in glyphosate-resistant Kochia scoparia. Planta 241:463-474. (published online in 2014).

Impact Statements

1.Information focused on applied research and extension to enhance pesticide resistance management was exchanged across disciplines, geographic regions, and systems. Members gained unique perspectives to guide their individual research, extension, and teaching efforts.
2.Through a variety of means, information on pesticide resistance and resistance management reached important audiences and stakeholders in the scientific community, in industry, and among regulators.
3.Specifically, publication of the Arthropod Pesticide Resistance Database (APRD), provided a resource used both by USEPA, EU and industry (IRAC International) authorities as well as pest managers in the US and internationally for resistance reporting for pesticide registration and pesticide reregistration processes as well as recommendations in resistance management.