Source: UTAH STATE UNIVERSITY submitted to NRP
THE ALFALFA INSECTICIDE MANAGEMENT (AIM) TOOLKIT: LINKING INSECTICIDE FATE MODELLING WITH ALFALFA PEST AND BENEFICIAL INSECT TOXICITY ENDPOINTS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
1020874
Grant No.
2019-70005-30363
Cumulative Award Amt.
$455,633.00
Proposal No.
2019-02810
Multistate No.
(N/A)
Project Start Date
Sep 1, 2019
Project End Date
Feb 28, 2023
Grant Year
2020
Program Code
[AFRP]- Alfalfa and Forage Program
Recipient Organization
UTAH STATE UNIVERSITY
(N/A)
LOGAN,UT 84322
Performing Department
Chemistry & Biochemistry
Non Technical Summary
The future of alfalfa seed and forage production in the western United States depends on the development of increasingly sophisticated insecticide management approaches that control pests effectively while avoiding an upsurge in insecticide resistance, improving profitability through reduced insecticide use, and maximizing the benefits derived from beneficial insect and pollinator services. These goals can be achieved by more precisely controlling when and for how long insects are exposed to lethal concentrations of insecticides on alfalfa foliage. We propose to accomplish this goal by making it possible to accurately predict insecticide dissipation rates from alfalfa foliage under various conditions and by creating a database of insecticide lethal concentrations on foliage for key alfalfa pests, beneficial insects, and managed pollinators. Our project objectives are to (1) optimize and validate a model designed to predict insecticide dissipation rates from alfalfa foliage, (2) create a database of relevant toxicity endpoints by conducting insecticide exposure experiments, (3) link the model to the database in our new Alfalfa Insecticide Management (AIM) Toolkit, (4) test the applicability of the AIM Toolkit in a field trial, and (5) obtain feedback from alfalfa seed and forage producers through a number of Extension activities. Alfalfa producers will benefit from the AIM Toolkit because it will reduce the guesswork surrounding many of the important decisions they make about insecticide application and will enable them to explore potential modifications to insecticide application approaches without conducting expensive field trials.
Animal Health Component
30%
Research Effort Categories
Basic
40%
Applied
30%
Developmental
30%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21616401060100%
Knowledge Area
216 - Integrated Pest Management Systems;

Subject Of Investigation
1640 - Alfalfa;

Field Of Science
1060 - Biology (whole systems);
Goals / Objectives
Goal Statement: To provide a mechanism for improving pest control and safeguarding beneficial insects and pollinators during alfalfa production.Objective 1: To optimize the ability of the Pesticide Loss from Agricultural Fields (PLAF) model for predicting insecticide loss rates from alfalfa leaves. Lab experiments will be conducted to measure key input parameters for alfalfa that are used in the model. Selected pesticides will then be applied to alfalfa seed and forage systems and loss rates from leaves will be measured to test and improve the model.Objective 2: To measure insecticide toxicity endpoints for several pest insects, beneficial insects, and managed bee species via a series of laboratory toxicity tests.Objective 3: To develop the AIM Toolkit by combining PLAF model with a database containing relevant toxicity endpoints from our experiments (Objective 2) and others found in the literature.Objective 4: To trial the AIM Toolkit in a test case designed to assess the relationship between pesticide persistence under different conditions and pesticide effectiveness against a pest insect.Objective 5: To undertake technology transfer through outreach and Extension activities.
Project Methods
Objective 1 Methods: Optimizing the PLAF model using field trials and lab experimentsSelected insecticides will be applied at typical (full field) application rates to alfalfa seed and forage systems near Logan, Utah on four occasions (each with different weather conditions). Complementary laboratory experiments will be conducted to generate input data for use in the PLAF model. Alfalfa leaf-air partition coefficients for each selected insecticide will be measured with a fugacity meter located in the Hageman Lab, with the effects of temperature and adjuvants on volatilization also being measured. Additionally, photochemical degradation rates of selected insecticides on alfalfa leaves will be measured under various light conditions with a solar simulator. Modelled insecticide dissipation rates will then be generated with the PLAF model, with the objective being to simulate the results observed for each field experiment.Objective 2 Methods: Measuring insecticide toxicity endpointsToxicity endpoints will be measured for two common alfalfa pest insects: alfalfa weevil (Hypera postica) (larvae and adults) and Lygus bugs (Lygus hesperus) (late instar nymphs and adults). Lygus bugs will be obtained from the USDA-ARS Arid Land Agricultural Research Center (confirmed by Colin Brent). Other insects will be collected from local plots and reared in our labs. We will use a two-tiered approach for toxicity testing by conducting two types of insecticide exposure tests, bottle bioassays and foliage residue tests. The advantage of the bottle tests is that they are straight-forward to conduct and are the standard tests used in insecticide resistance studies. The foliage residue tests, however, are more realistic since insects will be exposed to field-weathered insecticides on alfalfa foliage.Bottle bioassay tests are the standard tests used by the Center for Disease Control for assessing insect susceptibility to insecticides (CDC 2014, Denlinger et al. 2015, Denlinger et al. 2016). These techniques were established with arthropods that transmit diseases to humans, but will be optimized for use with the pests, predators, parasitoids, and pollinators that we will test in our study. We will follow the protocol outlined in the EPA's 'Honey Bee Toxicity of Residues on Foliage' test (US Environmental Protection Agency 2012) to identify residual insecticide concentrations in foliage that are lethal to the alfalfa pests, beneficial insects, and managed bee species. While this protocol was designed for honey bee risk assessment purposes, it is easily adapted to other insects as was shown in experiments designed to determine the residual insecticide contact toxicity on alfalfa foliage for the beneficial leafminer parasite, Diglyphus isaea (Chukwudebe et al. 1997).Objective 3 Methods: Development of Alfalfa Insecticide Management (AIM) ToolkitThe AIM Toolkit will combine the PLAF model with a database containing relevant toxicity endpoints for key alfalfa pests, beneficial insects, and managed pollinators. In addition to our toxicity measurements (Objective 2), the toxicity database will include all relevant endpoints that can be found in the literature.Objective 4 Methods: Use of AIM Toolkit in a test caseIn Wyoming, the hypothesis that early spring insecticide applications are more effective at alfalfa weevil management than summer applications due to higher insecticide persistence in the spring will be tested. Efficacy tests from Colorado State Extension (Peairs et al. 2015) have shown early spring application to be effective, but little is known about the mechanism. Given the different weather conditions and amount of plant biomass present earlier in the season, this may be due to higher insecticide persistence in spring. In collaboration with a local crop advisor scout and applicator (see Spencer letter of support), insecticide will be applied per grower preference either in early spring (April) or shortly before 1st cutting (June). Spencer will help Jabbour and her MS student make contact with growers prior to application, and they will select three fields with each timing from which to collect data. The experiment will be repeated in Years 1 and 2. An additional test location will be located at the University of Wyoming James C. Hageman Sustainable Agricultural Research and Extension Center in Lingle, WY. Jabbour planted alfalfa in a 2-acre blocks in Fall 2018 that will be divided into two 1-acre plots receiving each application timing to serve as a more accessible replicate for more detailed data collection.Objective 5 Methods: Technology transferCo-PDs Ramirez and Jabbour, at USU and Wyoming respectively, will guide the outreach strategy. Ramirez has an Extension appointment and Jabbour is in collaboration with Extension educators in alfalfa-producing regions of Wyoming who have expressed commitment to collaborate (see Vardiman and Schell letters of support). We will develop Extension materials to meet the short-term (gains in IPM knowledge) and long-term (change in behavior and adoption of effective IPM tools, e.g., AIM-toolkit) outcomes for our region. Each state's outreach goals will be met by a series of activities. To present published material, University of Wyoming will utilize the High Plains Integrated Pest Management website (https://wiki.bugwood.org/HPIPM), and USU will use the Utah Pests website (https://utahpests.usu.edu). Project updates and subject matter (i.e., weevil chemical control options, resistance issues, and AIM-toolkit), as deemed relevant will be published through university and industry newsletters, and blogs (e.g., Utah Pests Newsletter, Hay and Forage Grower, Wyoming Livestock Roundup). Targeting alfalfa growers, University of Wyoming Extension will present updates and findings at the annual Forage Field Day, which rotates at different locations around the state each year. Targeting insecticide applicators, University of Wyoming Extension will present project updates at annual pesticide certification workshops held in January. Jabbour will collaborate with county-based Extension educators to provide updates at local programming such as WESTI-Ag Days and at the annual Farm and Ranch Days conference. USU Extension will also present at two or more meetings such as the county Utah Crop Schools held annually, and the Utah Hay Conference held every other year in St. George, Utah (next one in 2021).Effort and Evaluation Plans Objectives 1-4 describe our planned efforts to increase knowledge about insecticide loss rates from agricultural fields and the concentrations that affect pests, beneficial insects, and managed bees. Objective 4 describes the effort we will make to transfer new knowledge to Extension services and growers. To evaluate our Extension program, we will use methods such as surveys on intent to adopt practices as measures of impact. It is also possible to use pre-post testing from a subset of our meetings to calculate percent gains in knowledge and intent to adopt IPM practices with t-test analysis. In Year 1 of the project, we will seek feedback from growers at these events on the types of decisions they would like to use the AIM toolkit to evaluate - for example, differential impact of morning vs midday vs evening sprays on pest insects and/or bees. Outreach goals within the context of our outcomes and outputs, such as short-term outcomes (gains in IPM knowledge) from on-site workshops will be assessed by standard pre-post testing methods. Numbers of printed bulletins purchased and pdf manuals downloaded will serve as indirect proxies for short-term outcomes (gains in IPM knowledge). We additionally will conduct post-workshop evaluations of audience intent to adopt our new IPM technology. These evaluations will provide insight to the expected intermediate-term (changes in behavior) and long-term (judicious insecticide use, i.e., improved environmental conditions) outcomes.

Progress 09/01/19 to 02/28/23

Outputs
Target Audience:Extension officers, alfalfa growers, integrated pest management specialists, bee keepers, pesticide application specialists, pesticide companies, pesticide regulators, environmental chemists. Changes/Problems:We were able to keep much of our work on schedule despite the pandemic; however, some adjustments were required. The most significant issue caused by the pandemic was restricted access to the experiment station in Lingle, Wyoming where we planned to conduct the Wyoming Test Case field experiments (Objective 4). These experiments were instead conducted in Spring 2021. Due to restricted access at the experiment station in Lingle, Wyoming, we conducted additional related experiments in Spring 2020 that could be done at the greenhouses on the University of Wyoming campus. These included two main sets of experiments. First, a field experiment testing how differences in insecticide timing affected alfalfa insects was conducted in 2020 and 2021. Second, two rounds of greenhouse experiments explored how pesticide (herbicide-insecticide) mixtures affect alfalfa and common weeds in alfalfa systems. These experiments explored how pesticide decisions (timing and mixtures) can potentially impact pest control. Although separate from the pesticide fate analysis, these experiments still serve as case studies on the impact of insecticide management decisions in alfalfa. These case studies were received with high interest and engagement by our stakeholders. What opportunities for training and professional development has the project provided?This project included training and mentoring of a number of students at the PhD, Masters, and undergraduate levels from the Departments of Chemistry, Biology, and Computer Science at USU and the Department of Plant Sciences at University of Wyoming. Student names and degrees are listed below. Ashlie Kinross - USU Chemistry, PhD student. Degree completed in Spring 2022. Rosalie Sepesy - USU Biology, PhD student. Degree is ongoing. Sean Lyons - USU Chemistry, Master's student. Degree completed in Spring 2021 and received the USU College of Science Masters Student of the Year Award. Micah McClure - U of Wyoming Plant Sciences, Master's student. Degree completed in Fall 2021. Calvin Luu - USU Chemistry, undergraduate researcher Anna Fabiszak - USU Chemistry, undergraduate researcher Connor Mead - USU Computer Sciences, undergraduate researcher Rebecca Bernhardt - USU Biology, undergraduate researcher Keith Wilson - USU Biology, undergraduate researcher Kaleb Keller - USU Biology, undergraduate researcher Landon Holmes - USU Biology, undergraduate researcher Rhett Greenwald - U of Wyoming Plant Sciences, undergraduate researcher How have the results been disseminated to communities of interest?In addition to disseminating our findings to communities of interest via publications, scientific conferences, and invited lectures (which have been described elsewhere in this report), we have engaged with a variety of stakeholders through formal and informal events throughout the project. The USU team delivered presentations about this project and gained feedback with stakeholders at the following meetings and events: Cache Co. Pesticide Applicators Training. (R. Ramirez) (2019) Box Elder Co. Pesticide Safety Training. (R. Ramirez) (2019) Kane/Garfield Co. Crop School. (R. Ramirez) (2020) Sevier County Crop School. (R. Ramirez) (2020) Wayne County Crop School. (R. Ramirez) (2020) Juab Co. Crop School. (R. Ramirez) (2019) Weber County Crop School. (R. Ramirez) (2019) American Mosquito Control Association (S. Bernhardt) (2021) EPA Office of Pesticide Programs meeting. (T. Pitts-Pinger) (2021) Western Alfalfa Seed Growers Conference (K. Hageman) (2022) Midwest Forage Association Symposium (K. Hageman) (2022) Utah Hay and Forage Symposium (S. Bernhardt) (2023) The University of Wyoming team discussed this project's findings at university Field Days throughout the state (Lingle, Powell, and Sheridan, which represent three of the main alfalfa growing regions) as well as by giving a virtual symposium that was also hosted in-person at county offices across the state. Communication with farmers and applicators in Wyoming was regularly maintained and they provided feedback on our experimental treatments and plans throughout the project. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? IMPACT STATEMENT: Through this project, we have created tools and knowledge for improving insecticide application strategies, both in terms of effectiveness against pests and protection of beneficial insects. This was accomplished by developing a model for predicting the behavior and dissipation rates of pesticides applied to crops, optimizing the model for alfalfa by conducting lab and field experiments, developing a database of lethal insecticide concentrations for beneficial and pest insects, and creating a user-friendly publicly available website for use by growers, pesticide applicators, extension agents, pesticide manufacturers, and scientists. Objective 1: To optimize the Pesticide Loss from Agricultural Fields (PLAF) model for predicting insecticide loss rates from alfalfa foliage under varying weather and field conditions. The model will be optimized for several of the most common insecticides currently used on alfalfa seed and forage plots as well as several alternatives. The Pesticide Dissipation from Agricultural Land (PeDAL) model was developed and then optimized for predicting insecticide loss rates from alfalfa foliage (the PLAF model was changed to PeDAL model). Initial evaluation was achieved by comparing modeled dissipation half-lives to those in the literature. This work is described in the publication, "Foliar photodegradation in pesticide fate modeling: Development and evaluation of the Pesticide Dissipation from Agricultural Land (PeDAL) model" (2021) by Lyons and Hageman (2021). We then conducted a series of field experiments with chlorpyrifos and -cyhalothrin applications on alfalfa seed and forage plots in Utah and Wyoming, respectively, to specifically optimize the model for alfalfa applications. We used lab experiments to measure (a) plant-air partition coefficients and foliar penetration rates for chlorpyrifos and -cyhalothrin on alfalfa leaves and (b) foliar photodegradation rates for chlorpyrifos, -cyhalothrin, and indoxacarb on alfalfa leaves. These data are reported in the publication, "Investigating the effects of temperature, relative humidity, leaf collection date, and foliar penetration on leaf-air partitioning of chlorpyrifos" (2022) by Kinross, Hageman, and Luu. Evaluation and optimization of a new instrumental technique for extracting pesticides from leaves is described in the publication, "Comparison of Accelerated Solvent Extraction (ASE) and Energized Dispersive Guided Extraction (EDGE) for the analysis of pesticides in leaves" (2020) by Kinross, Hageman, Doucette, and Foster. The comparison of measured and modeled concentrations showed good correlation during the first two days, but to account for biphasic behavior on days 2-7, we modified the leaf penetration data in the model. This work is described in Ashlie Kinross' PhD dissertation, "Pesticide-leaf interactions and their implications for pesticide fate modeling" (2022). Objective 2: To measure insecticide toxicity endpoints for several pest insects, beneficial insects, and managed bee species via a series of laboratory toxicity tests. Toxicity curves for the contact insecticides chlorpyrifos and λ-cyhalothrin were completed for alfalfa weevil larvae, lygus bugs, and alfalfa leafcutter bees. We identified the LC50 and LC90 for each chemical and insect to compare susceptibility. For chlorpyrifos, the LC50 for lygus is almost two times higher than for weevils, and the LC90 for lygus is around three times higher than for weevils. Reaching 90% mortality for weevils requires nearly six times the LC50. Reaching 90% mortality for lygus requires nearly 11 times the LC50. For λ-cyhalothrin, the LC50 for lygus and weevil are approximately the same, but the LC90 for weevils is about four times higher than for lygus. Reaching 90% mortality for weevils requires nearly 13 times the LC50. Reaching 90% mortality for lygus requires nearly five times the LC50. Bees were very susceptible to both chlorpyrifos and ?l-Cyhalothrin, and substantially more susceptible than either pest that we analyze. The concentrations needed to achieve desired mortality levels in the pests far surpassed even the LC 90 for bees. These results illustrate the concern for pollinators and other beneficial insects when balancing insecticide application. As insecticide resistance develops in pest insects, the risk for pollinators will continue to grow. This study also (a) demonstrated the translational capabilities of the CDC bottle assay from the public health field to agriculture settings and (b) produced data that will serve as a baseline for pest resistance to insecticides measures to be made. Objective 3: To develop the AIM Toolkit by combining PLAF model with a database containing relevant toxicity endpoints from our experiments (Objective 2) and others found in the literature. We conducted a thorough search of the literature for insecticide toxicity endpoints relevant to pests, beneficial insects, and pollinators important to alfalfa. We found that the only reliable endpoints available are for honey bees and bumble bees, highlighting the importance of this project's efforts to generate more toxicity data. We have currently compiled all available data from the literature and are in the process of adding toxicity data from Objective 2 to the website. An undergraduate student from the Computer Science Department at USU built a user-friendly web-based application that combines the PeDAL model with the toxicity database to predict risk quotients specific to insect species, field/meteorological conditions, and time after application. The website is called PesticideToolkit.usu.edu and is publicly available. Objective 4: To trial the AIM Toolkit in a test case designed to assess the relationship between pesticide persistence under different conditions and pesticide effectiveness against a pest insect. The test case experiments were conducted at University of Wyoming's alfalfa forage experimental fields located near Lingle, Wyoming in Spring 2021. Experiments were designed to compare the persistence of In addition (as referenced in the changes/problems section), we completed additional experiments in 2020-2021 to further project goals while adhering to the University of Wyoming's Covid-19 research restrictions. We tested the scenario originally proposed (early season vs. regular spray timing) for efficacy against alfalfa insect pests and beneficial insects in field experiments in both 2020 and 2021. In addition, we developed another line of questioning that explored pesticide effectiveness of herbicide-insecticide mixtures against alfalfa weeds in two rounds of greenhouse experiments. The timing effects data is described in the publication, "Insecticide application timing effects on alfalfa insect communities" (2023) by McClure, Herreid, and Jabbour. Objective 5: To undertake technology transfer through outreach and Extension activities. Our team actively engaged with a variety of stakeholders through formal and informal events and communication throughout the project. The USU team delivered presentations about this project and gained feedback from stakeholders at Entomological Society of America conferences (2020, 2022), with the EPA Office of Pesticide Programs (2021), at the Western Alfalfa Seed Growers Conference (2022), at the Midwest Forage Association Symposium (2022), at the Utah Hay and Forage Symposium (2023), and at the American Mosquito Control Association (2021). The University of Wyoming team discussed this project's findings at university Field Days throughout the state (Lingle, Powell, and Sheridan, which represent three of the main alfalfa growing regions) as well as a virtual symposium that was also hosted in-person at county offices across the state. Communication with farmers and applicators in Wyoming was also regularly maintained and they provided feedback on our experimental treatments and plans throughout the project.

Publications

  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Insecticide application timing effects on alfalfa insect communities (2023). McClure, M., Herreid, J., Jabbour, R. Journal of Economic Entomology. In press.
  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Investigating the effects of temperature, relative humidity, leaf collection date, and foliar penetration on leaf-air partitioning of chlorpyrifos (2022). Kinross, A., Hageman, K., Luu, C. Environmental Science and Technology. 56, 13058-13065.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Optimizing a pesticide fate model for use in predicting honeybee risk under different scenarios. Society of Environmental Toxicology and Chemistry (Pittsburgh) November 2022 Authors: Kimberly Hageman, Ashlie Kinross, Sean Lyons
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Entomological Society of America, Pacific Branch Meeting, Virtual April 2022 Title: Evaluating the toxicity of chlorpyrifos and lambda-cyhalothrin in alfalfa weevil (Hypera postica), Lygus bug (Lygus spp.), and alfalfa leafcutting bee (Megachile rotundata) Authors: Rosalie Sepesy, Scott Bernhardt, Ricardo Ramirez, Kimberly Hageman, Theresa Pitts-Singer
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Society of Environmental Toxicology and Chemistry (SETAC) Europe Meeting, Copenhagen May 2022 Title: Investigating the Effects of Temperature, Adjuvants, Relative Humidity, Collection Date, and Foliar Penetration on Leaf-Air Partitioning of Chlorpyrifos Authors: Kimberly Hageman, Ashlie Kinross, Calvin Luu
  • Type: Other Status: Published Year Published: 2021 Citation: Brigham Young University Department of Chemistry & Biochemistry Seminar Series November 2021 Title: Using Chemical Fate Modeling to Predict Pesticide Fate in Agricultural Fields Author: Kimberly Hageman
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Western Alfalfa Seed Growers Winter Seed Conference January 2022 Title: Introducing the Alfalfa Insecticide Management Toolkit Author: Kimberly Hageman
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Midwest Forage Association Symposium Lightning Session, Virtual February 2022 Title: Introducing the Alfalfa Insecticide Management Toolkit Author: Kimberly Hageman
  • Type: Theses/Dissertations Status: Published Year Published: 2021 Citation: Masters Thesis title: Pesticide Application Timing and Mixture Effects on Alfalfa Pests Author: Micah McClure, Department of Plant Sciences, University of Wyoming November 2021
  • Type: Theses/Dissertations Status: Published Year Published: 2022 Citation: PhD Dissertation title: Pesticide-Leaf Interactions and their Implications for Pesticide Fate Modeling Author: Ashlie Kinross, Department of Chemistry and Biochemistry, Utah State University
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Utah Hay and Forage Symposium, St. George UT, January 2023 Presentation Title: Alfalfa Insecticide Resistance Authors: Rose Sepesy, Scott Bernhardt, Ricardo Ramirez
  • Type: Other Status: Published Year Published: 2021 Citation: Virtual Webinar for Terrestrial Technical Team (TTT) in the Environmental Fate and Effects Division (EFED) in the EPA Office of Pesticide Programs November 2021 Title: Unique pesticide exposure routes for solitary cavity-nesting bees Author: Theresa Pitts-Singer
  • Type: Other Status: Published Year Published: 2021 Citation: Utah State University Undergraduate Research and Creative Opportunities Symposium December 2021 Title: Insecticide resistance of alfalfa pests, Hypera Postica and Lygus spp. using adapted CDC bottle assays for an agricultural setting Authors: Rebecca Bernhardt, Rose Sepesy, Scott Bernhardt
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: American Chemical Society Annual Conference August 2022 Title: Non-Apis bee life history traits pose unique agrochemical exposure routes Author: Theresa Pitts-Singer


Progress 09/01/21 to 08/31/22

Outputs
Target Audience:Extension officers, alfalfa growers, integrated pest management specialists, bee keepers, pesticide application specialists, pesticide companies, pesticide regulators, environmental chemists Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project included training and mentoring of a number of students at the PhD, Masters, and undergraduate levels from the Departments of Chemistry, Biology, and Computer Science at USU and the Department of Plant Sciences at University of Wyoming. Student names and degrees are listed below. Ashlie Kinross - USU Chemistry, PhD student. Degree completed in Spring 2022. Rosalie Sepesy - USU Biology, PhD student. Degree is ongoing. Sean Lyons - USU Chemistry, Master's student. Degree completed in Spring 2021 and received the USU College of Science Masters Student of the Year Award. Micah McClure - U of Wyoming Plant Sciences, Master's student. Degree completed in Fall 2021. Calvin Luu - USU Chemistry, undergraduate researcher Anna Fabiszak - USU Chemistry, undergraduate researcher Connor Mead - USU Computer Sciences, undergraduate researcher Rebecca Bernhardt - USU Biology, undergraduate researcher Keith Wilson - USU Biology, undergraduate researcher Kaleb Keller - USU Biology, undergraduate researcher Landon Holmes - USU Biology, undergraduate researcher Rhett Greenwald - U of Wyoming Plant Sciences, undergraduate researcher How have the results been disseminated to communities of interest?In addition to disseminating our findings to communities of interest via publications, scientific conferences, and invited lectures (which have been described elsewhere in this report), we have engaged with a variety of stakeholders through formal and informal events throughout the project. The USU team delivered presentations about this project and gained feedback with stakeholders at the following meetings and events: Cache Co. Pesticide Applicators Training. (R. Ramirez) (2019) Box Elder Co. Pesticide Safety Training. (R. Ramirez) (2019) Kane/Garfield Co. Crop School. (R. Ramirez) (2020) Sevier County Crop School. (R. Ramirez) (2020) Wayne County Crop School. (R. Ramirez) (2020) Juab Co. Crop School. (R. Ramirez) (2019) Weber County Crop School. (R. Ramirez) (2019) American Mosquito Control Association (S. Bernhardt) (2021) EPA Office of Pesticide Programs meeting. (T. Pitts-Pinger) (2021) Western Alfalfa Seed Growers Conference (K. Hageman) (2022) Midwest Forage Association Symposium (K. Hageman) (2022) Utah Hay and Forage Symposium (S. Bernhardt) (2023) The University of Wyoming team discussed this project's findings at university Field Days throughout the state (Lingle, Powell, and Sheridan, which represent three of the main alfalfa growing regions) as well as by giving a virtual symposium that was also hosted in-person at county offices across the state. Communication with farmers and applicators in Wyoming was regularly maintained and they provided feedback on our experimental treatments and plans throughout the project. What do you plan to do during the next reporting period to accomplish the goals?The justifications for requesting this extension are outlined below. The main reason for the NCE request (to Feb 28, 2023) is to utilize funding from the Direct Costs category to continue paying wages of our Computer Science undergraduate, Connor Mead, for development of the web application for this project. Connor has completed preparation of the core components and structure of the website, but is still in the process of incorporating all model equations and input parameters. It would also be beneficial to use remaining funds to pay Connor in Fall 2022 and the start of Spring 2 to continue trouble-shooting and optimizing the Toolkit, especially as we advertise the website more and obtain feedback from users about it. Finally, we would like him to spend more time future-proofing the website by completing a user's page and detailed instructions for updating the website. Tthere is also some remaining money in the Travel Budget. We would like to use these funds to support attendance at an upcoming NIFA Project Director's meeting if one occurs (no PD meetings were held during this project due to covid) and/or to present results at another conference.

Impacts
What was accomplished under these goals? IMPACT STATEMENT: Through this project, we have created tools and knowledge for improving insecticide application strategies, both in terms of effectiveness against pests and protection of beneficial insects. This was accomplished by developing a model for predicting the behavior and dissipation rates of pesticides applied to crops, optimizing the model for alfalfa by conducting lab and field experiments, developing a database of lethal insecticide concentrations for beneficial and pest insects, and creating a user-friendly publicly available website for use by growers, pesticide applicators, extension agents, pesticide manufacturers, and scientists. Objective 1: To optimize the Pesticide Loss from Agricultural Fields (PLAF) model for predicting insecticide loss rates from alfalfa foliage under varying weather and field conditions. The model will be optimized for several of the most common insecticides currently used on alfalfa seed and forage plots as well as several alternatives. The Pesticide Dissipation from Agricultural Land (PeDAL) model was developed and then optimized for predicting insecticide loss rates from alfalfa foliage (this is the PLAF model described in the proposal, with a name change). Initial evaluation of the model was achieved by comparing modeled dissipation half-lives to those reported in the literature for a variety of pesticides and crops. This work is described in the publication, "Foliar photodegradation in pesticide fate modeling: Development and evaluation of the Pesticide Dissipation from Agricultural Land (PeDAL) model" (2021) by Lyons and Hageman (2021). The initial comparison of measured and modeled insecticide concentrations in alfalfa leaves showed good correlation between loss rates during the first two days after application. However, actual concentrations in the field tended to be higher than modeled results during days 2-6. We attributed this to a biphasic loss mechanism in which increasing transfer of insecticide to the inner layer of leaves over time decreases volatilization and photodegradation. To account for this, we modified the leaf penetration data in the model and found this significantly improved the correlation. This work is described in Ashlie Kinross' PhD dissertation, "Pesticide-leaf interactions and their implications for pesticide fate modeling" (2022). Objective 2: To measure insecticide toxicity endpoints for several pest insects, beneficial insects, and managed bee species via a series of laboratory toxicity tests. Toxicity curves for the contact insecticides chlorpyrifos and λ-cyhalothrin were completed for alfalfa weevil larvae, lygus bugs, and alfalfa leafcutter bees. We identified the LC50 and LC90 for each chemical and insect to compare susceptibility. For chlorpyrifos, the LC50 for lygus is almost two times higher than for weevils, and the LC90 for lygus is around three times higher than for weevils. Reaching 90% mortality for weevils requires nearly six times the LC50. Reaching 90% mortality for lygus requires nearly 11 times the LC50. For λ-cyhalothrin, the LC50 for lygus and weevil are approximately the same, but the LC90 for weevils is about four times higher than for lygus. Reaching 90% mortality for weevils requires nearly 13 times the LC50. Reaching 90% mortality for lygus requires nearly five times the LC50. Bees were very susceptible to both chlorpyrifos and ?l-Cyhalothrin, and substantially more susceptible than either pest that we analyze. The concentrations needed to achieve desired mortality levels in the pests far surpassed even the LC 90 for bees. These results illustrate the concern for pollinators and other beneficial insects when balancing insecticide application. As insecticide resistance develops in pest insects, the risk for pollinators will continue to grow. This study also (a) demonstrated the translational capabilities of the CDC bottle assay from the public health field to agriculture settings and (b) produced data that will serve as a baseline for pest resistance to insecticides measures to be made. Objective 3: To develop the AIM Toolkit by combining PLAF model with a database containing relevant toxicity endpoints from our experiments (Objective 2) and others found in the literature. We conducted a thorough search of the literature for insecticide toxicity endpoints relevant to pests, beneficial insects, and pollinators important to alfalfa. We found that the only reliable endpoints available are for honey bees and bumble bees, highlighting the importance of this project's efforts to generate more toxicity data. We have currently compiled all available data from the literature and are in the process of adding toxicity data from Objective 2 to the website. An undergraduate student from the Computer Science Department at USU in the process of building a user-friendly web-based application that combines the PeDAL model with the toxicity database to predict risk quotients specific to insect species, field/meteorological conditions, and time after application. Objective 4: To trial the AIM Toolkit in a test case designed to assess the relationship between pesticide persistence under different conditions and pesticide effectiveness against a pest insect. The test case experiments were conducted at University of Wyoming's alfalfa forage experimental fields located near Lingle, Wyoming in Spring 2021. Experiments were designed to compare the persistence of In addition (as referenced in the changes/problems section), we completed additional experiments in 2020-2021 to further project goals while adhering to the University of Wyoming's Covid-19 research restrictions. We tested the scenario originally proposed (early season vs. regular spray timing) for efficacy against alfalfa insect pests and beneficial insects in field experiments in both 2020 and 2021. In addition, we developed another line of questioning that explored pesticide effectiveness of herbicide-insecticide mixtures against alfalfa weeds in two rounds of greenhouse experiments. The timing effects data is described in the publication, "Insecticide application timing effects on alfalfa insect communities" (2023) by McClure, Herreid, and Jabbour. Objective 5: To undertake technology transfer through outreach and Extension activities. Our team actively engaged with a variety of stakeholders through formal and informal events and communication throughout the project. The USU team delivered presentations about this project and gained feedback from stakeholders with the EPA Office of Pesticide Programs (2021), at the Western Alfalfa Seed Growers Conference (2022), at the Midwest Forage Association Symposium (2022), at the Utah Hay and Forage Symposium (2023), and at the American Mosquito Control Association (2021). The University of Wyoming team discussed this project's findings at university Field Days throughout the state (Lingle, Powell, and Sheridan, which represent three of the main alfalfa growing regions) as well as a virtual symposium that was also hosted in-person at county offices across the state. Communication with farmers and applicators in Wyoming was also regularly maintained and they provided feedback on our experimental treatments and plans throughout the project.

Publications


    Progress 09/01/20 to 08/31/21

    Outputs
    Target Audience:Extension officers, alfalfa growers, integrated pest management specialists, bee keepers, pesticide application specialists, pesticide companies, pesticide regulators, environmental chemists Changes/Problems:We were able to keep much of our work on schedule despite the pandemic; however, some adjustments were required. The most significant issue caused by the pandemic was restricted access to the experiment station in Lingle, Wyoming where we planned to conduct the Wyoming Test Case field experiments (Objective 4). These experiments were instead conducted in Spring 2021. Those experiments and the associate data analysis are now complete. However, this means that some of our technology transfer, conference presentations, and publishing (Objective 5) was also pushed into Year 3. Due to restricted access at the experiment station in Lingle, Wyoming, we conducted additional related experiments in Spring 2020 that could be done at the greenhouses on the University of Wyoming campus. These included two main sets of experiments. First, a field experiment testing how differences in insecticide timing affected alfalfa insects was conducted in 2020 and 2021. Second, two rounds of greenhouse experiments explored how pesticide (herbicide-insecticide) mixtures affect alfalfa and common weeds in alfalfa systems. These experiments explored how pesticide decisions (timing and mixtures) can potentially impact pest control. Although separate from the pesticide fate analysis, these experiments still serve as case studies on the impact of insecticide management decisions in alfalfa. Updates on these case studies have been received with high interest and engagement by our stakeholders. What opportunities for training and professional development has the project provided?The following students received training as part of this project: Two PhD students (Ashlie Kinross - USU Chemistry, Rosalie Sepesy - USU Biology) Two Masters students (Sean Lyons - USU Chemistry, Micah McClure - U of Wyoming Plant Sciences). Sean Lyons completed his Master's degree in Spring 2021 and received the USU College of Science Masters Student of the Year Award. Seven undergraduate researchers (Calvin Luu - USU Chemistry, Anna Fabiszak - USU Chemistry, Rebecca Bernhardt - USU Biology, Keith Wilson - USU Biology, Kaleb Keller - USU Biology, Landon Holmes - USU Biology, Rhett Greenwald - U of Wyoming Plant Sciences) How have the results been disseminated to communities of interest?The PeDAL model and approaches for incorporating foliar photodegradation into other insecticide fate models has been made available to pesticide companies, pesticide regulators, environmental chemists through our publication (Lyons and Hageman, 2021) and research presentations at conferences (the Society of Environmental Chemistry and Toxicology, the American Chemical Society). Our team has been actively engaged with a variety of stakeholders through formal and informal events and communication. In the past year, the University of Wyoming team has discussed this project's findings at university field days throughout the state (Lingle, Powell, and Sheridan represent three of the main alfalfa growing regions) as well as a virtual symposium that was also hosted in-person at county offices across the state. We also maintain regular communication with farmers and applicators in the state, who provided feedback on our experimental treatments and plans throughout the project. What do you plan to do during the next reporting period to accomplish the goals?Remaining tasks for this project are listed below. We plan to complete all lab experiments, data analysis, and interpretation by the project end date (August 31, 2022). We aim to submit all manuscripts to journals by that point; however, some may still be going through the review process. Objective 1: Further optimization of the PeDAL model to better account for decreased loss rate following Day 2 due to biphasic processes. Complete publication describing plant-air partition coefficients and foliar penetration. Complete publication describing photodegradation rates, field trials, and further optimization of PeDAL model. Objective 2: Complete toxicity testing. Complete publication describing toxicity test results. Objective 3: Complete and publish web application for AIM Toolkit. Objective 4: Complete publication on insecticide timing effects on alfalfa insects. Objective 5: Continue to present results, promote AIM Toolkit, and obtain feedback from potential users at upcoming scientific conferences, grower meetings, farm days, etc.

    Impacts
    What was accomplished under these goals? Objective 1: To optimize the Pesticide Loss from Agricultural Fields (PLAF) model for predicting insecticide loss rates from alfalfa foliage under varying weather and field conditions. The model will be optimized for several of the most common insecticides currently used on alfalfa seed and forage plots as well as several alternatives. Basic model development occurred during the first reporting period. During development, the model name was changed to the Pesticide Dissipation from Agricultural Land (PeDAL) model. Initial evaluation of the model was achieved by comparing modeled dissipation half-lives to those reported in the literature for a variety of pesticides and crops, as described in the publication by Lyons and Hageman (2021). During the most recent reporting period, we conducted field experiments with chlorpyrifos and -cyhalothrin applications on alfalfa seed and forage plots in Utah and Wyoming, respectively, to specifically optimize the model for alfalfa applications. We also used lab experiments to measure (a) plant-air partition coefficients for chlorpyrifos and -cyhalothrin on alfalfa leaves and (b) foliar photodegradation rates for chlorpyrifos, -cyhalothrin, and indoxacarb on alfalfa leaves. The partition coefficients and photodegradation rates are now being used as inputs in the PeDAL model. Comparison of measured and modeled insecticide concentrations in alfalfa leaves has shown good correlation between loss rates during the first two days after application. However, actual concentrations in the field tend to be higher than modeled results during days 2-6. We attribute this to a biphasic loss mechanism in which increasing transfer of insecticide to the inner layer of leaves over time decreases volatilization and photodegradation. Thus, a follow-up plan is being developed to modify the model to account for this effect. Objective 2: To measure insecticide toxicity endpoints for several pest insects, beneficial insects, and managed bee species via a series of laboratory toxicity tests. Toxicity curves for the contact insecticides chlorpyrifos and λ-cyhalothrin were finalized for alfalfa weevil larvae, lygus bugs, and alfalfa leafcutter bees. We identified the LC50 and LC90 for each chemical and insect to compare susceptibility.For chlorpyrifos, the LC50 for lygus is almost two times higher than for weevils, and the LC90 for lygus is around three times higher than for weevils. Reaching 90% mortality for weevils requires nearly six times the LC50. Reaching 90% mortality for lygus requires nearly 11 times the LC50. For λ-cyhalothrin, the LC50 for lygus and weevil are approximately the same, but the LC90 for weevils is about four times higher than for lygus. Reaching 90% mortality for weevils requires nearly 13 times the LC50. Reaching 90% mortality for lygus requires nearly five times the LC50. Bees were much more susceptible to both insecticides compared to weevils and lygus. The LC50 for bees for chlorpyrifos was three times lower compared to weevils and five times lower compared to lygus. The LC50 for bees for λ-cyhalothrin was two times lower compared to weevils and about the same as lygus. For both chemicals, doubling the LC50 results in 90% mortality. Feeding assays were started for each insect to develop toxicity curves for the ingestion-based insecticides indoxacarb and flupyradifurone. These feeding curves will be used in the same way as the contact data. Time response trials were started to identify diagnostic concentrations for the contact insecticides. Diagnostic concentrations were defined as the concentration at which 100% of a test population dies between 30 and 60 minutes. These data will be used to compare susceptibility between populations. Objective 3: To develop the AIM Toolkit by combining PLAF model with a database containing relevant toxicity endpoints from our experiments (Objective 2) and others found in the literature. We conducted a thorough search of the literature for insecticide toxicity endpoints relevant to pests, beneficial insects, and pollinators important to alfalfa. We found that the only reliable endpoints available are for honey bees and bumble bees, highlighting the importance of this project's efforts to generate more toxicity data. We have currently compiled all available data from the literature and will add toxicity data from Objective 2 as it continues to be generated and finalized. We hired an undergraduate student from the Computer Science Department at USU to build a user-friendly web-based application that combines the PeDAL model with the toxicity database to predict risk quotients specific to insect species, field/meteorological conditions, and time after application. A low-fidelity version of the application is complete. Construction of the high-fidelity version is currently underway. Objective 4: To trial the AIM Toolkit in a test case designed to assess the relationship between pesticide persistence under different conditions and pesticide effectiveness against a pest insect. The test case experiments were conducted at University of Wyoming's alfalfa forage experimental fields located near Lingle, Wyoming in Spring 2021. Experiments were designed to compare the persistence of In addition (as referenced in the changes/problems section), we completed additional experiments in 2020-2021 to further project goals while adhering to the University of Wyoming's Covid-19 research restrictions. We tested the scenario originally proposed (early season vs. regular spray timing) for efficacy against alfalfa insect pests and beneficial insects in field experiments in both 2020 and 2021. In addition, we developed another line of questioning that explored pesticide effectiveness of herbicide-insecticide mixtures against alfalfa weeds in two rounds of greenhouse experiments. Although the greenhouse experiments do not measure pesticide persistence as needed for the AIM toolkit, they do address pesticide effectiveness in alfalfa systems. Objective 5: To undertake technology transfer through outreach and Extension activities. Our team has been actively engaged with a variety of stakeholders through formal and informal events and communication. In the past year, the University of Wyoming team has discussed this project's findings at university field days throughout the state (Lingle, Powell, and Sheridan represent three of the main alfalfa growing regions) as well as a virtual symposium that was also hosted in-person at county offices across the state. We also maintain regular communication with farmers and applicators in the state, who provided feedback on our experimental treatments and plans throughout the project.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2021 Citation: Foliar photodegradation in pesticide fate modeling: Development and evaluation of the Pesticide Dissipation from Agricultural Land (PeDAL) model (2021). Lyons, S.M., Hageman, K.J. Environmental Science and Technology 55, 4842-4850
    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Comparison of Accelerated Solvent Extraction (ASE) and Energized Dispersive Guided Extraction (EDGE) for the analysis of pesticides in leaves (2020). Kinross, A.D., Hageman, K.J., Doucette, W.J., Foster, A.L. Journal of Chromatography A. 461414
    • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Combining insecticide fate modeling and insect toxicity thresholds for improved pesticide management American Chemical Society Conference, Division of Agricultural and Food Chemistry (Virtual) August 2021 Authors: Ashlie Kinross, Sean Lyons, Kimberly Hageman
    • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: The Pesticide Dissipation from Agricultural Land (PeDAL) model & its use in pesticide management and risk assessment Society of Environmental Toxicology and Chemistry Conference, Europe (Virtual) May 2021 Authors: Kimberly Hageman, Sean Lyons, Ashlie Kinross
    • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Determining translational effectiveness of the CDC bottle assay for monitoring insecticide resistance in arthropod field populations American Mosquito Control Association (Virtual) March 2021 Authors: Scott A. Bernhardt, Shawna Hennings, Rose Sepesy, Ricardo Ramirez, Kimberly Hageman
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Insecticide application timing effects on pests and beneficial insects in alfalfa Entomological Society of America Annual Meeting (virtual) November 2020 Authors: Micah McClure, Randa Jabbour 1st Place President⿿s Prize for best talk in IPM Field Crops Section 2
    • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Predicting pesticide fate in agricultural fields and developing the Alfalfa Insecticide Management (AIM) Toolkit Utah State University, Department of Biology Seminar Series March 2021 Authors: Kimberly Hageman, Sean Lyons, Rosalie Sepesy
    • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Using chemical fate modeling to predict pesticide fate in agricultural fields Truman State University, Department of Chemistry Seminar Series January 2021 Author: Kimberly Hageman
    • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Unique pesticide exposure routes for solitary cavity-nesting bees Virtual Webinar for Terrestrial Technical Team (TTT) in the Environmental Fate and Effects Division (EFED) in the EPA Office of Pesticide Programs November 2021 Author: Theresa Pitts-Singer
    • Type: Theses/Dissertations Status: Published Year Published: 2021 Citation: Foliar Photodegradation of Pesticides in Environmental Modeling Masters Degree Thesis, Utah State University March 2021 Author: Sean Lyons


    Progress 09/01/19 to 08/31/20

    Outputs
    Target Audience:Extension officers, alfalfa growers, integrated pest management specialists, bee keepers, pesticide application specialists, pesticide companies, pesticide regulators, environmental chemists Changes/Problems:Due to the coronavirus pandemic, research at the University of Wyoming James C. Hageman Sustainable Agricultural Research and Extension Center was restricted and therefore the majority of data collection originally planned for 2020 and 2021 will instead take place during 2021 and 2022, respectively (using a no-cost extension). Due to restrictions in activities during the summer of 2020 and a delay in producing results from the Wyoming test case, some planned outreach activities and conference presentations will also be conducted in the summer of 2022 (Year 3). What opportunities for training and professional development has the project provided?Four graduate students and one undergraduate student are currently being trained as part of this project. These include: A PhD and MS student in the Department of Chemistry and Biochemistry at Utah State University. These students have been responsible for Objective 1 and are splitting one of the RA positions from the grant. The PhD student has been conducting lab experiments focused on measuring leaf-air partition coefficients and finalizing analytical chemistry methods for the insecticides being used in the study. The MS student has been responsible for development of the PeDAL model, field experiments to validate the PeDAL model, and photochemistry experiments. An undergraduate student in the Department of Chemistry and Biochemistry at Utah State University has become involved in this project. He is assisting the PhD and MS students with lab and field experiments and associated analytical work. An MS student in the Department of Biology at Utah State University. This student has been responsible for conducting the toxicology experiments and generating dose-response curves (Objective 2). An MS student in the Department of Plant Sciences at University of Wyoming (funding via sub-contract). This student has been conducting experiments relevant to Objective 4. How have the results been disseminated to communities of interest?Extension Activities in Utah Seven presentations have been delivered to farmers, agricultural professionals, and extension county faculty as part of the Utah Crop School circuit. These presentations highlight alfalfa pest management, including insecticide use and a brief overview of this project's objectives. These initial presentations provide a framework for subsequent outreach presentations as research results become available. Ramirez, R.A. 2019. Managing arthropod pests and beneficials in alfalfa and corn. Cache Co. Pesticide Applicators Training. Dec. 3. Logan, UT Ramirez, R.A. 2019. Beneficial insect ID and how insects buildup insecticide resistance. Box Elder Co. Pesticide Safety Training. Dec 19. Tremonton, UT Ramirez, R.A. 2020. Research update on aphids and weevil in Utah. Kane/Garfield Co. Crop School. Jan 15. Bryce Canyon, UT Ramirez, R.A. 2020. Insect control and management-weevil, aphid, and mites. Sevier County Crop School. JAN 16. Richfield, UT. Ramirez, R.A. 2020. Weevil management in alfalfa. Wayne County Crop School. JAN 17. Loa, UT. Ramirez, R.A. 2020. Alfalfa insect management. Juab Co. Crop School. JAN 23. Nephi, UT. Ramirez, R.A. 2020. Alfalfa insect management. Weber County Crop School. JAN 30. Farr West, UT. Extension Activities in Wyoming Dr Jabbour delivered a presentation on alfalfa insect pest management and introduced this project specifically at a series of Wyoming Hay and Forage Association events in three locations (Powell, Casper, and Torrington, WY). Participation included a total of ~120 producers, many of whom were excited about this project and shared with us their observations about altering spray timing practices. In addition, this research is being shared via the Jabbour Group Instagram Site (@weevilwarriors), which has ~400 followers. What do you plan to do during the next reporting period to accomplish the goals?Objective 1: Three additional insecticide applications will take place during Summer 2020 on the alfalfa seed plot at Greenville farm. All three applications will be of chlorpyrifos so that we can evaluate how the insecticide fate is affected by crop and meteorological conditions. We will evaluate how well the PeDAL model predicts the pesticide behavior. If there are discrepancies between measured and modelled results, we will re-visit model design and make improvements. We will continue laboratory experiments designed to determine the air-leaf equilibrium coefficients. The results from these experiments provide information about how quickly pesticides volatilize from alfalfa leaves and will be used as input parameters in the PeDAL model. As part of these experiments, we will evaluate how adjuvants in pesticide formulations affect volatilization rates. We will continue laboratory experiments designed to determine photodegradation rates of pesticides on alfalfa leaf surfaces. These rates will be used as input parameters in the PeDAL model and help predict pesticide behavior in alfalfa fields. Objective 2: We will continue laboratory experiments designed to determine the dose-response curves and LD50s for pests, beneficial insects, and managed bees that are important to alfalfa growers. Toxicity endpoints will be measured for two common alfalfa pest insects: alfalfa weevil (Hypera postica) (larvae and adults) and Lygus bugs (Lygus hesperus) (late instar nymphs and adults). Lygus bugs will be obtained from the USDA-ARS Arid Land Agricultural Research Center (confirmed by Colin Brent). Other insects will be collected from local plots and reared in our labs. We will use a two-tiered approach for toxicity testing by conducting two types of insecticide exposure tests, bottle bioassays and foliage residue tests. The advantage of the bottle tests is that they are straight-forward to conduct and are the standard tests used in insecticide resistance studies. The foliage residue tests, however, are more realistic since insects will be exposed to field-weathered insecticides on alfalfa foliage. Objective 3: We will develop the Alfalfa Insecticide Management (AIM) Toolkit by linking the PeDAL model (Objective 1) and the toxicology database (Objective 2). The AIM Toolkit will feature a web-based user-friendly interface where users can select an insecticide from a drop-down menu and then specify the application rate, the parameters that describe their field and crop, the weather conditions, and the insect of interest. The drop-down menu will retrieve the physiochemical properties from a built-in pesticide database. Our current pesticide database includes 224 pesticides and more will be added; however, if the insecticide of interest is not already in our pesticide properties database, users will be able to add the physiochemical properties of their insecticide of interest. In Year 2, we will employ a computer science undergraduate student for four months to help develop the Graphical User Interface. The interface will be developed using R Shiny, or a similar program. Objective 4: We will test the hypothesis that early spring insecticide applications are more effective at alfalfa weevil management than summer applications due to higher insecticide persistence. Given the different weather conditions and amount of plant biomass present earlier in the season, this may be due to higher insecticide persistence in spring. We will compare the effectiveness of application strategies by evaluating field data as well as predicted results from the AIM Toolik. Our goal is to determine the degree to which the AIM Toolkit can be used to predict how application strategies compare. In grower fields, insecticide loss rates will be measured by collecting alfalfa leaves multiple times per day for six days after application. After collection, leaves will be immediately stored on ice in glass vials. Leaf samples will be shipped to the Hageman Lab where insecticide concentrations (total amounts in leaves as well as on leaf surfaces only) will be quantified to determine insecticide dissipation rates. Factors that affect insecticide fate (i.e. temperature, wind speed, light intensity, leaf density) will be monitored in the field during and after insecticide application. Pest and beneficial insects will be quantified at all fields in the early spring, prior to any insecticide application. We will use vacuum sampling to collect insects from alfalfa foliage, as this is particularly effective in the early season when there is little foliage to sweep. Samples will be timed (30 seconds per sample) and we will collect six samples per field (each 20 m apart). The same sampling practice will be used one week following the early application, and again prior to and one week following the summer application. All fields will be visited in between the first and second cutting to score alfalfa damage and collect an additional round of vacuum samples. All samples will be sorted to quantify alfalfa weevils, damsel bug predators, lady beetles, minute pirate bugs, parasitoid wasps, and bees. Objective 5: We will continue to address our outreach and technology transfer goals over the next two years. To present published material, University of Wyoming will utilize the High Plains Integrated Pest Management website (https://wiki.bugwood.org/HPIPM), and USU will use the Utah Pests website (https://utahpests.usu.edu). Project updates and subject matter (i.e., weevil chemical control options, resistance issues, and AIM-toolkit), as deemed relevant will be published through university and industry newsletters, and blogs (e.g., Utah Pests Newsletter, Hay and Forage Grower, Wyoming Livestock Roundup). Targeting alfalfa growers, University of Wyoming Extension will present updates and findings at the annual Forage Field Day, which rotates at different locations around the state each year. Targeting insecticide applicators, University of Wyoming Extension will present project updates at annual pesticide certification workshops held in January. Jabbour will collaborate with county-based Extension educators to provide updates at local programming such as WESTI-Ag Days and at the annual Farm and Ranch Days conference. USU Extension will also present at two or more meetings such as the county Utah Crop Schools held annually, and the Utah Hay Conference held every other year in St. George, Utah (next one in 2021). To evaluate our Extension program, we will use methods such as surveys on intent to adopt practices as measures of impact. It is also possible to use pre-post testing from a subset of our meetings to calculate percent gains in knowledge and intent to adopt IPM practices with t-test analysis. We will continue to seek feedback from growers at these events on the types of decisions they would like to use the AIM toolkit to evaluate - for example, differential impact of morning vs midday vs evening sprays on pest insects and/or bees.

    Impacts
    What was accomplished under these goals? Objective 1: A. Model Development During the course of model development, we selected an alternative name for the PLAF model and it is now called the Pesticide Dissipation from Agricultural Lands (PeDAL) model. PeDAL model development and validation is now complete. The PeDAL model was designed to predict pesticide fate in an agricultural field after application under various scenarios. The processes included in the model are pesticide volatilization from soil and plant surfaces, photodegradation from plant surfaces, and foliar penetration. A useful output parameter that PeDAL produces is the time needed for a pesticide's concentration to reach half of the initial concentration after its application (the DT50). The PeDAL model predicts pesticide volatilization rates using the Pesticide Loss via Volatilization (PLoVo) model, which was also developed by our research team. The primary contribution that this publication will make to the research field is introduction of an advanced approach for incorporating photodegradation rates into pesticide fate models. Previously developed pesticide fate models use a simplistic single rate constant for pesticide photodegradation. In contrast, we use photodegradation rates that are specific to the pesticide and adjusted for solar intensity. B. Optimization of PeDAL model for predicting insecticide loss rates from alfalfa Our approach for optimizing the PeDAL model for alfalfa involves measuring insecticide loss rates, using field experiments, for several days following application. To validate the model, we will compare measured results to those predicted by the PeDAL model. Model inputs include field, crop, and meteorological data measured in the field during pesticide application. Four insecticide applications will take place during Spring/Summer 2020 on an alfalfa seed plot at the Greenville Research Farm, Utah Agricultural Experiment Station. We will conduct four field experiments, one with Warrior II (active ingredient: lambda-cyhalothrin, a pyrethroid insecticide) and three with Chlorpyrifos 4E-AG (active ingredient: chlorpyrifos, an organophosphate insecticide). This series of experiments will allow us to evaluate PeDAL model performance with regard to (a) varying physicochemical characteristics of the insecticide and (b) varying crop and meteorological conditions. If discrepancies between modelled and measured values are discovered, we will re-visit the model design and make improvements. Field experiment #1 took place during the week of May 18, 2020. Warrior II was applied by hand sprayer at the maximum recommended rate on an 0.1-acre plot of alfalfa at the Greenville Farm. Background leaf and soil samples were collected one week and one day prior to application and leaf and soil samples were collected at various time points starting immediately following application until one week after application. Detailed meteorological data (including temperature, relative humidity, wind speed, and solar radiation) was collected at the farm site every 15 minutes for the entire sampling period. In addition to meteorological data, all necessary parameters describing the field, crop, and soil conditions that are used as inputs in the PeDAL model were collected. C. Laboratory experiments Experiments to measure alfalfa leaf-air equilibrium partition coefficients for several insecticides are currently underway in the Hageman Lab. We have completed alfalfa leaf-air partition coefficient measurements over a range of temperatures for chlorpyrifos (both as an active ingredient alone and in a formulation) and flupyradifurone (active ingredient). Experiments to measure insecticide photodegradation rates on alfalfa leaves are underway in the Hageman Lab using an Atlas SunTest CPS+ solar simulator. Chemical actinometry experiments using a p-nitroanisole/pyridine actinometer are complete and the intensity of light produced by the solar simulator has been determined. The next step is to begin photodegradation experiments with insecticides on alfalfa leaves to obtain photodegradation rates. Objective 2: Initial bottle assay experiments are currently being conducted with active ingredient insecticides to obtain baseline data without interference from adjuvants in insecticide formulations. Upcoming experiments will be conducted with formulations for comparison. The first series of bottle assays were conducted with weevil larvae, which began to emerge in local alfalfa fields in late May 2020. Weevils were collected via sweep netting from two alfalfa fields in close proximity. 25-30 larvae were used in each bottle/assay chamber and each insecticide concentration was replicated three times. Larvae were exposed to an insecticide for 1 hour and then moved to a cage containing five alfalfa leaves. After 24 hours, mortality was measured and values were entered into the QCal software program for generation of dose-response curves. Our first experiments focused on generating dose-response susceptibility curves for chlorpyrifos. Dose and replicate exposure data are also actively being collected for lambda-cyhalothrin, indoxacarb, and flupyradifurone. Dr. Bernhardt and graduate student Rose Sepesy are evaluating the susceptibility curves for each of the insecticides to ensure a sufficient number of replicates and concentrations are conducted to determine LD50 and LD90 concentrations. Since the alfalfa weevil season is finite and limited, all focus has been on obtaining curves specific to the weevil. As the weevil larval loads reduce to zero in the field, susceptibility and diagnostic dose curve data will then begin to be collected on other insects of interest (e.g. alfalfa leafcutting bees, lygus bugs). USDA ARS Pollinating Insects Research Unit has purchased alfalfa leafcutting bees from Canada and has acquired bees from Utah/Idaho bee managers. Objective 3: We will focus on this objective after additional progress has been made on Objectives 1 and 2. Objective 4: Spring 2020 experiments have focused on applying Warrior II (active ingredient: lambda-cyhalothrin) at an experimental farm at two timings. The aim of these experiments is to determine how insect control aligns with predictions about insecticide concentrations from the PeDAL model. This will allow us to better target timings/data collection for future summers. Due to the coronavirus pandemic, research at the University of Wyoming James C. Hageman Sustainable Agricultural Research and Extension Center was restricted and therefore the majority of data collection originally planned for 2020 and 2021 will instead take place during 2021 and 2022, respectively (using a no-cost extension). Objective 5: A. Extension activities in Utah Seven presentations have been delivered to farmers, agricultural professionals, and extension county faculty as part of the Utah Crop School circuit. These presentations highlight alfalfa pest management, including insecticide use and a brief overview of this project's objectives. These initial presentations provide a framework for subsequent outreach presentations as research results become available. B. Extension activities in Wyoming Dr Jabbour delivered a presentation on alfalfa insect pest management and introduced this project specifically at a series of Wyoming Hay and Forage Association events in three locations (Powell, Casper, and Torrington, WY). Participation included a total of ~120 producers, many of whom were excited about this project and shared with us their observations about altering spray timing practices. In addition, this research is being shared via the Jabbour Group Instagram Site (@weevilwarriors), which has ~400 followers.

    Publications

    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Society of Environmental Toxicology and Chemistry (SETAC), Toronto, November 2019 Presentation Title: The Pesticide Loss from Agricultural Field Model Authors: Sean Lyons (presenter), Kimberly Hageman