Progress 09/01/19 to 08/31/23
Outputs
Target Audience:Target audiences for our efforts included soyean farmers and associated agricultural professionals (crop consultants,sales agronomists, applicators), and other scientists working with agricultural pests. Changes/Problems:Changes to this project were described in previous reports. These included complications due to research restructions related to the COVID-19 pandemic,problems with equipment availability, and challenges with getting adequate attendance for focus groups. However, we were able to successfully overcome these challenges to address project goals. What opportunities for training and professional development has the project provided?This projectfacilitated thetraining of three graduate students. From Entomology, one recently graduate and is stating a job with an agricultural company;and the other student, recently transitioned from MS to PhD degree. From Applied Economics, one student recently graduated. How have the results been disseminated to communities of interest?As indicated above, updates on results of this research have have been presetned at various scientific conferences. Lozano, R., T. Hurley, J. Knodel, D.A. Andow and R.L. Koch. 2023, April. Upper Midwest farmers' soybean aphid management practices and perceptions on insecticide resistance. 10-minute presentation. Meeting of the North Central and Soutwestern Branches of the Entomological Society of America. Oklahoma City, OK. Heshmatpour, M., T. Hurley, J. Knodel, D.A. Andow and R.L. Koch. 2022, November. Pyrethroid resistance concerns and changing soybean aphid (Aphis glycines Matsumura) management: Evidence from the Midwest United States. 10-minute presentation. Meeting of the Entomological Society of America. Vancouver, BC, Canada. Lozano, R., A.R.I. Lindsey, D.P. Paula, D. Andow and R.L. Koch. 2022, November. Population genetics of the soybean aphid voltage-gated sodium channel gene. 10-minute presentation. Meeting of the Entomological Society of America. Vancouver, BC, Canada. Lozano, R., A.R.I. Lindsey, D.P. Paula, D. Andow and R.L. Koch. 2022, March. Variability in mutations in the voltage-gated sodium channel among soybean aphid populations. 10-minute presentation. Meeting of the North Central Branch of the Entomological Society of America. Minneapolis, MN. Lozano, R., A. Lindsey, D.P. Paula, D.A. Andow and R.L. Koch. 2021, October. Soybean aphid resistance to pyrethroid insecticides: Variability in target-site mutations among and within fields. Student competition 10-minute presentation. Meeting of the Entomological Society of America. Denver, CO. Lozano, R., D.P. Paula, D.A. Andow and R.L. Koch. 2020, November. Validation of reference genes across populations of Aphis glycines Matsumura for RT-qPCR analysis of gene expression related to pyrethroid detoxification. Student competition 10-minute presentation. Meeting of the Entomological Society of America. Virtual meeting. However, dissemination of the results of this project to farmers and agricultural professionals has been relatively limited to date, due to the increased time that was required to complete this work. Koch, R.L. 2021, February. Rethinking insecticide-based management for soybean aphid. Soybean Breeders' Workshop. Virtual Meeting (20-minute presentation) Koch, R.L. 2022, September. Updates on soybean insect research and management. Advanced Ag Professional Insect and Disease Workshop. University of Minnesota, Extension. Rosemount, MN (45-minute presentation with 12 attendees). Koch, R.L. 2022, January. Continuing and new challenges in soybean insect management. Research Updates for Agricultural Professionals, Institute for Agricultural Professionals, University of Minnesota Extension. (30-minute presentation; Waseca: 31 attendees; Rochester: 26 attendees; Lamberton: 24 attendees; Morris: 26 attendees; Willmar: 30 attendees). Koch, R.L. 2021, February. Managing soybean aphid and insecticide resistance. County Crops Day on the Radio (KDHL), University of Minnesota Extension Rice and Steele Counties (30-minute presentation via radio) Koch, R.L. 2020, February. Soybean insect updates: aphids, gall midges and defoliators. Annual Meeting of Minnesota Independent Crop Consultants Association. Hutchison, MN (90-minute talk with 35 attendees). Koch, R.L. 2020, January. Soybean entomology updates: Soybean aphid, soybean gall midge and defoliators. Field Crop Pest Management Recertification, University of Minnesota Extension. (50-minute talk; Faribault: 101 attendees; Rochester: 146 attendees; St. Cloud: 55 attendees). Koch, R.L. 2019, December. Guidance for insecticide rotations for pyrethroid-resistant soybean aphid. Crop Pest Management Short Course. Minnesota Crop Production Retailers and University of Minnesota Extension. Minneapolis, MN (two 50-minute talks with 300 and 50 attendees). However, now that the work is complete, updates and recommendations from this research will be disseminated to farmers and agricultural professionals beginning this winter. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
1. Quantify spatio-temporal variability in soybean aphid susceptibility to pyrethroids. Infested plant material with live soybean aphids was collected and placed in a cooler from fields in the state of Minnesota in 2019 (12 fields), 2020 (10 fields) and 2021 (10 fields). The samples from 2019 were contributed to this project from other efforts in our laboratory. The aphids were used to assess aphid phenotype with a glass-vial bioassay. Within each year, mortality of soybean aphids exposed to bifenthrin differed significantly among. In all years, mortality of aphids from the insecticide-susceptible laboratory population treated with bifenthrin and lambda cyhalothrin was 100%. Mortality of the field-collected populations treated with bifenthrin ranged from 0% to 100% in 2019 and 2020, and from 30% to 100% in 2021. In the case of lambda cyhalothrin the mortality of soybean aphids exposed was significantly different between populations for the 2019 and 2020 2. Estimate the frequency of kdr or skdr mutations and level of overexpression of target detoxifying enzymes. Target site Target-site resistance is the primary mechanism involved in pyrethroid resistance across many insect species. This is the first study to assess diversity in the voltage-gated sodium channel (VGSC) gene, the target site for pyrethroids, of individuals from 32 field-collected soybean aphid populations throughout the state of Minnesota, US. Using Amplicon sequencing (Amplicon-seq) of a region of the VGSC gene associated to pyrethroid resistance of individual aphids collected across Minnesota, we identified 33 variants including four variants previously characterized for their role in conferring pyrethroid resistance (M918l, M918L, L925M, and L1014F), and 43 unique haplotypes indicating high diversity among the soybean aphid populations. Overall, 55.4% of all the haplotypes and 74.0% of the soybean aphids had at least one resistance-associated variant. Given the diversity of patterns across insects with regards to the haplosufficiency of target-site mediated pyrethroid resistance, we used our complementary genetic and mortality data to determine if there were any population level correlations between susceptibility and genotype. For bifenthrin, mortality was negatively correlated with the proportion of soybean aphids with any two resistance-associated haplotypes, regardless of zygosity (R*/R*). In the case of lambda cyhalothrin, mortality was negatively correlated with the proportion of soybean aphids that were heterozygous for different resistance-associated haplotypes (Ra/Rb). Broadly, the presence of resistance variants can be significant contributors to pyrethroid resistance in soybean aphids and poses a considerable challenge for pest control programs that rely on pyrethroids as a primary method of control. Understanding the genetic basis of pyrethroid resistance and monitoring its prevalence in soybean aphids can help to develop new control strategies for managing this pest in agricultural settings. Metabolic detox Metabolic detoxification is a common mechanism of insecticide resistance, in which detoxifying enzyme genes are overexpressed. There were no validated reference genes to normalize expression of detoxification genes for pyrethroid resistance in soybean aphid, therefore we first validated reference genes to facilitate our proposed work on metabolic detoxificationSix genes were identified with the greatest stability across technical and biological replication and the nine populations. To evaluate metabolic detoxification, soybean aphids were collected from four fields in Minnesota in 2019 and 2020 (representing a subset of the populations described above in goal 1). Aphids from these fields were phenotyped with the diagnostic concentration bioassay and all aphids (dead or alive) were immediately flash frozen. We measured the expression of nine detoxifying enzyme genes that were previously found to be constitutively overexpressed in pyrethroid-resistant clonal soybean aphid laboratory populations. We also measured two internal reference genes that we found the be the most suitable for the study of detoxifying enzymes related to pyrethroid resistance in soybean aphid. Expression was compared between live and dead individuals from the four soybean aphid populations. For bifenthrin, status (dead vs. alive) and the interaction between status and collection location was only significant for AglyCYP4C1-like variant 8. For lambda-cyhalothrin, the interaction between status and location was significant for AglyCYP4C1-like variant 11 and AglyCYP4C1-like variant 8. Overall, we found no strong evidence that enzyme-mediated detoxification is a major mechanism of pyrethroid resistance in these Minnesota soybean aphid populations. 3. Elucidate factors influencing soybean grower behavior and decision-making related to soybean aphid management and response to insecticide resistance. A survey of soybean farmers in Minnesota and North Dakota was conducted in 2021. Overall, the reported decision-making sources were similar for both farmers who changed and those who did not change their aphid management due to insecticide resistance; these were crop consultants and agricultural retailers. The threshold used by farmers in both groups to determine whether to use a foliar insecticide was lower than the research-based threshold for soybean aphid, and farmers were aware that this could be a practice that can contribute to insecticide resistance. Additionally, farmers who changed soybean aphid management were more concerned about insecticide resistance and were implementing good practices such as scouting, using label application rates, and rotating insecticide modes of action. However, more education is necessary to effectively manage insecticide resistance. The results of this research can help inform refinement of integrated pest management and insecticide resistance management programs as well as extension education efforts. 4) Disseminate research-based resistance management recommendations to stakeholders. Updates on results of this research have have been presetned at various scientific conferences. Dissemination of the results of this project to farmers and agricultural professionals has been relatively limited to date, due to the increased time that was required to complete this work. However, now that the work is complete, updates and recommendations from this research will be disseminated to farmers and agricultural professionals beginning this winter.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2023
Citation:
Lozano, R.E. 2023. Insecticide Resistance Management for Aphis glycines (Hemiptera: Aphididae): Understanding the Biological Mechanisms and Farmer Practices. PhD Dissertation, University of Minnesota. 201 pp.
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Progress 09/01/21 to 08/31/22
Outputs
Target Audience:Target audiences for our efforts will include soyean farmers and associated agricultural professionals (crop consultants, sales agronomists, applicators, etc.), and other scientists working with agricultural pests. Changes/Problems:There were numerous delays to the project due to covid and equipment failures, etc. However, due to gracious extensions of the timeline for this project, we are excited about completing this work within the recently approved extension to 2023. What opportunities for training and professional development has the project provided?This project continues to allow for training of graduate students. How have the results been disseminated to communities of interest?Validation of the reference genes for our upcoming work on detoxificaiton enzymes was published in a scientific journal. The results of the work on target site mutations were presented at the2022meeting of the North Central Branch of the Entomological Society of America in Minneapolis, MN,and updates will be presented at the 2022 meeting of the Entomological Society of America in Vancouver, BC. An overview of the project was presented at the recent NIFA project managers meeting. Results of practical relevance to farmers are still relativley limited, due to the setbacks described in the previous report. We continue to update agricultural professionals about the work at meetings. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, we should complete analyses of samples for the resistance mechanisms. We will then complete analysis of those data anddata from thesurvey of farmer attitudes about resistance. These results will enable to develop extension recommendations for growers and will provide the foundation for scientific papers that we will write.
Impacts
What was accomplished under these goals?
Quantify spatio-temporal variability in soybean aphid susceptibility to pyrethroids. Infested plant material with live soybean aphids was collected and placed in a cooler from fields in the state of Minnesota during the years 2020and 2021. The aphids were used to assess aphid phenotype with a glass-vial bioassay. Briefly, glass vials were treated with concentrations of bifenthrin or lambda-cyhalothrin that should kill 99% of susceptible aphids. Ten aphids were transferred into each of four vials of each insecticide treatment plus a similar number of untreated vials (40 aphids for each treatment; two insecticides and intreated control. Aphid mortality in the vials was assessed after 4 hours. Aphids from the bioassays were flash-frozen and preserved for molecular analysis to assess genotype. The bioassays showed statistically significant differences in insecticide susceptibility among the soybean aphid populations. Interestingly, there was more variability among populations for bifenthrin than lambda-cyhalothrin across the different locations. Results from the molecular work will help understand the variability of the soybean aphid resistance mechanisms. Estimate the frequency of kdr or skdr mutations and level of overexpression of target detoxifying enzymes. Metabolic detox Based on our previous detoxification enzyme work (Paula et al., 2020, https://doi.org/10.1016/j.pestbp.2019.12.012), we choose nine enzymes that showed to be constitutively overexpressed in all treatments of the resistant clonal populations as potential candidates. The expression of these enzymes was evaluated using qRT-PCR across two of the 2020 bioassayed soybean aphid field samples (dead and alive) that showed greater phenotypic resistance. To normalize gene expression, we used the top two most stable reference genes that we previously validated for these specific experimental conditions (Lozano et al. 2022, https://doi.org/10.18474/JES21-38). Preliminary results did not show significant differences in the gene expression between dead and alive aphids. Target site In our previous report, we explained the methods to determine single-nucleotide polymorphisms (SNPs) in the soybean aphid voltage gated sodium channel (VGSC). The VGSC gene appears associated with pyrethroid resistance in soybean aphid (Paula et al., 2021, https://doi.org/10.1127/entomologia/2021/1226). We performed performing Next Generation Sequencing on samples from 2019, 2020, and 2021 leveraging the UMN Genomics Center resources. Preliminary results show a suite of point mutations, some of which have been previously associated with pyrethroid resistance in other arthropod species (M918L, M918I, L925M and L1014F). We identified that L1014F is the most common variant across the locations analyzed. The data is still processing, and more results will be included in a future report. 3) Elucidate factors influencing soybean grower behavior and decision-making related to soybean aphid management and response to insecticide resistance. A quantitative mail survey was developed and sent to soybean farmers in MN and ND. Results of this survey have been compiled and analyses are underway.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Lozano, R.*, D.P. Paula, D.A. Andow and R.L. Koch. 2022. Validation of reference genes across populations of Aphis
glycines (Hemiptera: Aphididae) for RT-qPCR analysis of gene expression related to pyrethroid detoxification. Journal of Entomological Science. 57 (2), 213-239
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Progress 09/01/20 to 08/31/21
Outputs
Target Audience:Target audiences for our efforts will include soyean farmers and associated agricultural professionals (crop consultants, sales agronomists, applicators, etc.), and other scientists working with agricultural pests. Changes/Problems:In the previous report, I described the challenges posed by a later than aniticpated start to the project in 2019, which forced us to collect our first samples in 2020 instead of 2021. In that report, I also described theproblems encountered in 2020 with COVID-related restrictions on work and travel, and the breakdown of the colleges shared RT-qPCR machine. We are, however, successfully overcoming these challenges despite a significant delay. In 2020, we were pleased to be able to collect aphids from 10 locations, despite the restrictions on work and travel. We made arrangements with the UMN Genomics Center to assist with the work described earlier on target site mutations. We also gained access to a different 384-well RT-qPCR machine for our upcoming work with detoxification enzymes. More recently, however, the ultra-low freezer in which we were storing our samples broke and could not be replaced. We gained temporary access to a freezer in a different lab, but we will soon be purchasing a new ultra-low freezer to ensure we can complete this work. Currently, however, the severe drought conditions in Minnesota have suppressed soybean aphid infestations across the Midwest. Therefore, we may be limited in our ability to collect populations to assess for this work. To ensure we'll have some aphids to work with, we have collected the limited amount of aphids we could find from several fields and are increasing their numbers under lab conditions. We will then phenotype and genotype these aphids as in the previous year. As described in this report, we leveraged newly available data in Minnesota to developa quantitative survey on farmer attitudes and perspectives about insecticide resistance, instead of performing a less robust series of focus groups that would only provide quantitative data. The initial plan was for the focus groups to provide a foundation for such a quantitative survey, so this is a great advancement in our efforts to understand how farmer think about and deal with these challenges. What opportunities for training and professional development has the project provided?This project has allowed us to begin training a graduate student. She will be performing the field and laboratory entomology research. Recently, this student was selected to be part of the Entomological Society of America's first chort forProfessional Advancement Career Training (PACT) Initiative, which is asoft and leadership skills program. How have the results been disseminated to communities of interest?Validation of the reference genes for our upcoming work on detoxificaiton enzymes was published in a scientific journal and was presented at the 2020 meeting of the Entomological Society of America. Results of practical relevance to farmers are still relativley limited, due to the setbacks described in the previous report. We continue to update agricultural professionals about the work at meetings. In 2021, however, the drought conditions minimized the significance of soybean aphid, so our extension efforts were focused more on other pests that are more problematic under drought conditions. What do you plan to do during the next reporting period to accomplish the goals?Resistance mechanisms For the work on target site mutations, we are anxiously awaiting receipt of the sequence data from the UMN Genomics Center. Upon receipt data will be appropriately analyzed to determine the proportion of individual aphids with one or more of the different resistance-causing mutations. For the work on detoxification enzymes, we recently gained access to another large 384-wellRT-qPCR machine to replace the one we were previously using until it broke down in 2020. With access to this machine and with the reference genes validated, we'll begin work to determine expression profiles of the selected detoxificaiton enzymes in our samples of aphids. Farmer attitudes and perspectives The survey is nearly complete and will soon be sent for printing. The goal is to send this to randomly selected farmers after this years crop harvest and to have the results by the end of 2021.
Impacts
What was accomplished under these goals?
Resistance mechanisms To understand the biological mechanisms of pyrethroid resistance for soybean aphid (Aphis glycines Matsumura) we are focusing on two mechanisms of insecticide resistance documented in insects: metabolic detoxification (MD) and target site insensitivity (TSI). To determine the role of MD and TSI, we collected soybean aphids from 10 fields in 2020 (with five locations per field) to assess: (1) differences in the expression of genes encoding for enzymes that might have a role in pyrethroid detoxification, and (2) screen for mutations in the soybean aphid voltage-gated sodium channel (VGSC), the target of pyrethroid insecticides. In addition, we are currently collecting aphids for a second field season (2021). We have extracted RNA and synthesized cDNA for all 2020 field collected soybean aphids. The cDNA is the starting material to proceed with the pyrethroid resistance mechanisms analysis (see below). Metabolic detox:We will assess the expression of 13 enzymes across the soybean aphid samples using qRT-PCR. A major hurdle in carrying out such a project is developing and validating a set of reference genes that will allow us to normalize expression calculations across any differences in samples that might be due to processing and handling. We completed reference gene selection and validation, and a manuscript about the work on was accepted for publication in a peer reviewed journal, the Journal of Entomological Science (Lozano et al., in press). Target site:Currently, we are working on identifying mutations in the Aphis glycines VGSC, which is the target of the pyrethroid insecticides. We previously identified a region of this gene which consistently contains resistance mutations in lab colonies of soybean aphids (Paula et al 2021). Now we are determining the genetic diversity in this resistance region in the field populations using a Next Generation Sequencing (NGS) approach that includes a Nextera library preparation. For the Nextera library preparation, we developed a Nextera-compatible primer set specific to the Aphis glycines VGSC region of interest. Use of these custom Nextera primers required substantial optimization for different characteristics of the Polymerase Chain Reaction (PCR). Some of these optimizations include performing gradient PCRs to select the optimal annealing temperature, and testing PCR additives such as DMSO and BSA to eliminate DNA secondary structures. Finally, we found that the addition of the Nextera primers directly to the reaction did not yield good amplification. Therefore, we now have an optimized workflow that includes a primary PCR with only the gene primers (selected region for analysis), followed by a secondary PCR (with the first PCR product as the starting material) with the Nextera primers. All 2020 samples have been processed and amplified with the Nextera primers, and will soon be sent to the UMN Genomics Center for library completion and sequencing. Farmer attitudes and perspectives To understand farmer attitudes and perspectives toward soybean aphid managment and insecticide resistance, we developed a quantitative hardcopy (mail) survey based on newly available data in Minnesota. Because of this new data, we are able to transition to this more thorough quantitative approach instead of performing the previously planned qualitative focus groups. Currently the survey is being reviewed and commented on by Extension educators and farmers, to ensure all questions are clear, necessary and non-offensive. IRB approval for the survey is also being sought and will surely be granted based on experience with other surveys.
Publications
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2022
Citation:
Lozano, R.*, D.P. Paula, D.A. Andow and R.L. Koch. 2022. Validation of reference genes across populations of Aphis glycines (Hemiptera: Aphididae) for RT-qPCR analysis of gene expression related to pyrethroid detoxification. Journal of Entomological Science xx(x): xx-xx (in press)
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Progress 09/01/19 to 08/31/20
Outputs
Target Audience:Target audiences for our efforts will include soyean farmers and associated agricultural professionals (crop consultants, sales agronomists, applicators, etc.), and other scientists working with agricultural pests. Changes/Problems:When writing the proposal, we anticipated starting this research project prior to the 2019 field season (see timeline in project narrative); however, the project was ultimately established with a start date of September 2019. Considering this time, we were unable to collect field samples of soybean aphid for the 2019 field season, because aphid populations leave the the field by that time. When we were ready to fully staff the project for 2020, two major unforseen challenges emerged (COVID19 and a breakdown of the RT-qPCR machine). COVID19 and uncertainty about associated research restrictions delayed full staffing of this project in 2020. However, with the the delayed staffing, we did manage to collect and preserve some field samplesof soybean aphids from 2020. Unfortunately, we were unable to process/analyze the samples from 2020 because our college's shared RT-qPCR machine broke. We were left waiting for a considerable amount of time while management decided if they were going to fix or replace the equipment. Recently, we learned that it will not be fixed nor replaced, so we are exploring options for contracting services from the U of MN Genomics Center to process/analyze our samples, but will likely need approval to reallocate funds within the budget to do so. We are in discussion with staff from the Genromics Center to determine their capabilities and costs. What opportunities for training and professional development has the project provided?This project has allowed us to begin training a graduate student. She will be performing the field and laboratory entomology research. As the projectprogresses, we will work with her to identify relevant opportunitites for training and professional development. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, bioassay results will be analyzed to compare insecticide resistance levels among populations. In addition, RNA extractions and cDNA conversions will be performed with the samples collected and preserved from 2020. We then plan to proceed with assessment of detoxification enzymes (27 different enzymes and 6 references genes) and target site mutations (4 point mutations) using RT-qPCR facilities at the U of MN Genomics Center. Finally, we will plan to refine plans for and implement the focus groups.
Impacts
What was accomplished under these goals?
Cost-effective management of soybean aphid relies on threshold-based applications of insecticides. However, the soybean aphid has recently evolved resistance to one of the most commonly used groups of insecticides (i.e., pyrethroids). With few other pest management tools, the magnitude and mechanisms of this resistance problem needs to be assessed and research-based resistance management recommendations developed and disseminated. We proposed two research-focused objectives to: 1) determine the geographic and temporal variability soybean aphid resistance to pyrethroids; and 2) determine genetic and physiological components related to pyrethroid resistance in soybean aphid. We also proposed two complementary extension focused objectives to: 3) characterize attitudes of soybean growers toward soybean aphid management and insecticide resistance; and 4) disseminate the results and management recommendations developed by this project. Overall results of this project will mitigate the potential economic and environmental costs associated with insecticide resistance in this pest. 1) Quantify spatio-temporal variability in soybean aphid susceptibility to pyrethroids. In summer 2020, we collected soybean aphid populations from ten fields in Minnesota.In each field, aphids were collected from five locations at least 20 meters apart from one another. Aphids from each location were collected in two ways: 1. flash frozen in the field using liquid notrogen, and 2. plant material infested with live aphids was placed in a cooler. In the laboratory, the flash-frozen aphids were stored properly in RNAlater in a freezer for subsequent molecular work to assess genotype (see below). The live aphids were used to assess aphid phenotype with a glass-vial bioassay.Briefly, glass vials were treated with concentrations of bifenthrin or lambda-cyhalothrin that should kill 99% of susceptible aphids. Tenaphids were transferred into each of four vials of each insecticide treatment plus a similar number of untreated vials (40 aphids for each treatment; two insecticides and intreated control.Aphid mortality in the vials was assessed after 4 hours.Aphids from the bioassays (both live and dead) were preserved as described above for molecular to assess genotype. Data from the bioassays continue to be analyzed and will be presented in a later progress report. 2) Estimate the frequency of kdr or skdr mutations and level of overexpression of target detoxifying enzymes. Genetic material from the samples described above have been preserved. However, we have been unable to process/analyze these samples, because the college's shared RT-qPCR machine unexpectedly broke (see section on Changes/Problems). We are currently exploring options for contracting with the U of MN Genomics Center to process/analyze these samples. 3) Elucidate factors influencing soybean grower behavior and decision-making related to soybean aphid management and response to insecticide resistance. A planning meeting was held with staff from MN Extension and the MN soybean growers' assocation. During this meeting discussions focussed on narrowing down the targeted audience and the list of quesitons. It is hoped that we can finalize these details and perform the focus groups during the winter of 2020-2021. These will then be reported on in a later progress report. 4) Disseminate research-based resistance management recommendations to stakeholders. Consideirng the inability to start the research in 2019 and challenges encounterred in 2020 (see section on Changes/Problems), minimal project results have been accumulated. Despite this, extension presentations during this reporting period have emphasized the importance of insecticide resistance management for soybean aphid and provided an overview of what this project will address. Bioassay results indicating soybean aphid phenotypes will be included in extension efforts for winter 2020-2021 and results of genotyping work will hopefully be inlcuded in such efforts for summer 2021 and later.
Publications
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