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Publications: Crop Protection

PresentationsCrop Protection2020

Towards an efficient and improved approach for assessing risks of pesticides to endangered species in the United States: Methomyl case study

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ACS 2020, AGRO 178
Session Title: Integrating Species Conservation with Pesticides from Bench to Market
Available Monday, August 17, 2020 at 8:00am

Abstract:

Under the Endangered Species Act, the US Environmental Protection Agency (EPA) and the Services (National Marine Fisheries Service and Fish & Wildlife Service) are required to assess potential risks to threatened and endangered (listed) species as part of the process to register pesticides. EPA issued interim guidance for developing biological evaluations (BE) for pesticides in 2015. Since then, the EPA, the Services, the regulated community and others have continued to develop and refine national endangered species risk assessment (ESRA) methodologies, first with 3 organophosphates and recently with two carbamates, carbaryl and methomyl. In March 2020, EPA issued revised guidance for conducting BEs. Much, however, remains to be done to develop the most efficient, practical and scientifically defensible approach. Therefore, we are developing an improved scientific approach with methods that more efficiently screen out listed species that are not at risk earlier in the tiered assessment process. The approach begins with simple methods such as off-ramping (e.g., screening out listed species that have no potential for exposure); conservative, protective screening-level risk assessments to screen out entire receptor groups that are tolerant of exposure; and co-occurrence analyses to screen out species not present in pesticide use areas. We are developing spatially explicit, species-specific tools for each major receptor group to determine which listed species are potentially at risk using more advanced, but still protective, methods. Using methomyl as a case study, we demonstrate how these early tier methods can efficiently reduce the formidable scope of a national ESRA to focus on those listed species most at risk. The latter species would then proceed to probabilistic, more refined modeling and proper weight-of-evidence assessments.

D. Moore (Intrinsik), S. Teed (Intrinsik), C. Priest (Stone), M. Winchell (Stone), H. Rathjens (Stone), A. Frank (CSI), J. Giddings (CSI), M. Kern (Balance EcoSolutions), N. J. Snyder (Waterborne), T.M. Blickley (Corteva Agriscience), P.L. Havens (Dow AgroSciences).
Towards an efficient and improved approach for assessing risks of pesticides to endangered species in the United States: Methomyl case study. AGRO 178, ACS 2020. Virtual Meeting.

PresentationsAgriculture and Food, Crop Protection2020

Impact of climate change on the relevance of TFD studies and OECD crosswalks

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ACS 2020, AGRO 235
Session Title: Sustainability in Agriculture: Understanding the Environmental Footprint of Developing Crop Protection Products
Monday, August 17, 2020 8:00AM

Abstract:

Climate change studies confirm that the earth is warming up and that shifts in rainfall patterns is occurring. Various computer models predict that Earth’s average temperature will rise between 1.8° and 4.0° Celsius (3.2° and 7.2° F). Consequently, these warmer temperatures will cause a higher rate of evaporation, resulting in a predicted increase of average global rainfall by 3-5%. This climate change, therefore, will impact the relevance of historical and current terrestrial field dissipation (TFD) studies. Under OCED guidance, TFD studies conducted in one country can be applicable to other countries if the characteristics of overlapping ecoregions are the same. These assessments are conducted using the OECD ENASGIPS tool. If these characteristics change, so will the similarity assessment and therefore the potential relevance of TFD sites. With increase rainfall, TFD sites in the Southeastern US, which typically have few similar areas, may become more relevant because other areas are receiving more rainfall. Likewise, TFD sites in Canada, characterized by cold winters, may become more applicable to larger areas in Europe with increasing temperature. In this presentation we will review some of the climate change scenarios, place existing TFD sites in context of new climates and determine the impact on OECD crosswalks.

C. Hoogeweg, A. Ritter (Waterborne). Impact of climate change on the relevance of TFD studies and OECD crosswalks. AGRO 235, ACS 2020. Virtual Meeting

PresentationsAgriculture and Food, Crop Protection2020

Novel approaches for assessing management of tile-drain agricultural chemical transport

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ACS 2020, AGRO 214
Session Title: Off-target Transport of Field Applied Agricultural Chemicals
Monday, August 17, 2020 8:00AM

Abstract:

The study of conservation best management practices and their effectiveness at mitigating the off-site transport of agricultural chemicals is an established research field. While runoff and erosion have received much study focus, there is a growing need for new and novel approaches to monitor nutrients in tile-drained systems. A sophisticated water monitoring system was developed that utilizes technology to create an automated pass-through sampling site, employing state of the art nutrient sensor technology to monitor nitrate concentrations in thirty-seven discrete subsurface agricultural drainage tile laterals at a sampling rate of between two and four hours per sample at each tile. This design has proven highly efficient and provides a data resolution that would be impractical to consider under conventional sampling methods. It also allows for the replicated study of several treatments (different mitigation practice approaches) and control plots, with little additional cost per added plot. Additional benefits include the ability to view data in real-time, allowing researchers to observe real-time rainfall event-based plot responses without the analytical results delay from a laboratory. The developed site data provides the needed resolution for tile drain model validation or developments.

G. Goodwin (Waterborne), L. Gentry (Illinois Corn Growers Association), P. Paulausky, J. Trask, A. Jacobson, A. Ritter (Waterborne). Novel approaches for assessing management of tile-drain agricultural chemical transport. AGRO 214, ACS 2020. Virtual Meeting.

PresentationsCrop Protection2020

Consideration of non-Apis bee species in pollinator risk assessment

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ACS 2020, AGRO 164
Session Title: Extending the Boundaries of Pollinator Research and Risk Assessment Methodologies for Pesticides
Monday, August 17, 2020 8:00AM

Abstract:

The pollinator risk assessment process for pesticides from regulatory agencies, including USEPA, PMRA, and CDPR, have historically relied on the Western honeybee (Apis mellifera) as a surrogate species to represent all Apis and non-Apis bees. However, the life-history characteristics of non-Apis bee species, including solitary, stingless, and bumble bees, indicate differences from the surrogate honeybee species. These differences introduce uncertainty in the exposure and effects assumptions for the use of honeybees as a surrogate species, leading to the recent efforts of examining risk of pesticides to non-Apis species. The objective of this presentation is to provide a current state-of-the-science update on the specific life-history characteristics and specific risk assessment considerations for non-Apis species. Exposure assumptions will be examined and comparative toxicological sensitivities will be presented with recommendations for appropriate use in the pollinator risk assessment framework. Challenges in the development of non-Apis laboratory testing methods will also be presented.

J. Collins, J. Jackson, A. Ritter, A. Schmolke (Waterborne). Consideration of non-Apis bee species in pollinator risk assessment. AGRO 164, ACS 2020. Virtual Meeting.

PresentationsCrop Protection2019

Topeka shiner populations in the context of multiple stressors: a hybrid modeling approach

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SETAC 2019, Platform 687
Toronto, Ontario, Canada
Session Title: Integrating Pest Management, Risk Assessment and Environmental Sustainability
Thursday, November 7, 2019
10:00 am, Room 718B

Abstract:
Threatened or endangered species face challenges to their continued existence from multiple stressors. For example, habitat loss and modification were indicated as substantial threats to the Topeka shiner (Notropis topeka), a small cyprinid fish endemic to the US Midwest, when it was listed under the Endangered Species Act. Topeka shiner habitats are associated with intensive row crop agriculture, overgrazing, urbanization, road construction, and hydrologic alteration. However, assessments of risks to the species are usually limited to individual factors, such as direct effects from potential exposures to pesticides. We developed a hybrid modelling approach to assess Topeka shiner population dynamics and viability within the context of multiple factors including physical habitat characteristics, water quality, and land management practices. Topeka shiner habitat restoration efforts in Iowa are focused on restoring oxbows. Therefore, we simulated physical and chemical characteristics of these oxbow habitats, including their food web structure, as well as aspects of Topeka shiner biology and ecology. Land management was modeled indirectly by characterizing associated alterations of environmental inputs to the modeled oxbow. Land management influences included alterations to oxbow hydrology, temperature, light exposure, and influxes of nutrients, sediments, and pesticides. We analyzed scenarios of realistic ranges of these conditions in Iowa oxbows to assess their implications for long-term population dynamics of the Topeka shiner. With this hybrid modeling approach, we present a methodology for integrated assessments of ecological risks posed by land management and benefits of conservation measures designed to recover listed species. This modelling approach is intended to complement endangered species assessment by informing conservation/stewardship activities in an effort to enhance species viability.

A. Schmolke (Waterborne), S. Bartell (Cardno), C. Roy (Waterborne), N. Green (Waterborne), D. Perkins (Waterborne), N. Galic (Syngenta), R. Brain (Syngenta). Topeka shiner populations in the context of multiple stressors: a hybrid modeling approach. Platform 687, SETAC 2019. Toronto, Ontario, Canada.

PostersCrop Protection2019

Sources, characteristics and opportunities for pesticide use and usage information applied to listed species risk assessment

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SETAC 2019, RP225
Toronto, Ontario, Canada
Session Title: Integrating Pest Management, Risk Assessment and Environmental Sustainability
Thursday, November 7, 2019
8:00 am, Exhibit Hall

Abstract:
The challenges inherent in national-level pesticide endangered species risk assessments are many, varied and have been the topic of meetings, workshops, presentations and publications for many years. One challenge is the identification and incorporation of pesticide usage information in the risk assessment process. Pesticide “usage” differs from pesticide “use”, where “use” is defined by registered labels and describes limits on how the pesticide may be applied (i.e., maximum rates and number of applications), while “usage” describes documented applications with specific information on each individual event. Incorporating usage information into the risk characterization during the Biological Evaluation and Biological Opinion development process is an area of renewed interest. This poster will describe several sources of pesticide usage information (e.g., USDA Agricultural Chemical Use Program, CA DPR Pesticide Use Reporting), and how relevant field-level pesticide application information can be extracted. Examples will be given showing how these data can be utilized to refine our understanding of specific active ingredients and their associated spatial and temporal variation across use areas, and how this can inform the exposure analysis within each Step of the ESA consultation process.

C. Holmes (Applied Analysis Solutions), J. Amos (Waterborne), M. Kern (Waterborne), N. Snyder (Waterborne), J. Cowles (TKI), K. Henry (TKI).  Sources, characteristics and opportunities for pesticide use and usage information applied to listed species risk assessment. Poster, SETAC 2019. RP225. Toronto, Ontario, Canada.

PresentationsCrop Protection2019

Pop-GUIDE: Population modeling Guidance, Use, Interpretation, and Development for Ecological Risk Assessment

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SETAC 2019, Platform 475
Toronto, Ontario, Canada
Session Title: Incorporating New Approach Methodologies to Improve Ecological Risk Assessment – Part 1
Wednesday, November 6, 2019
11:00 am, Room 718B

Abstract:
The assimilation of population models into the Ecological Risk Assessment (ERA) process has been hindered by their range of complexity, uncertainty, resource investment, and data availability. Likewise, translating model outputs into endpoints that can be used by risk assessors has been challenging. Recent research efforts have begun to tackle these challenges by creating an integrated Modeling Framework and Decision Guide to aid the development of population models with respect to ERA objectives and data availability. In the Framework, the trade-offs associated with the generality, realism, and precision of an assessment are used to guide the development of a population model commensurate with the protection goal. The Decision Guide provides risk assessors with a stepwise process to assist them in developing a conceptual model that is appropriate for the assessment objective and available data. We have merged the Decision Guide and Modeling Framework into a comprehensive approach for the development of population models for ERA that is applicable across regulatory statutes and assessment objectives. In Phase 1 of Pop-GUIDE (Population modeling Guidance, Use, Interpretation, and Development for Ecological Risk Assessment), an approach is presented to guide assessors through the trade-offs of ERA generality, realism, and precision and translate these trade-offs into model objectives. In Phase 2, available data are assimilated and characterized as general, realistic, and/or precise. Phase 3 provides a series of dichotomous questions to develop a conceptual model that matches the complexity and uncertainty appropriate for the assessment that is in concordance with the available data. This phase guides model developers and users to ensure comprehension and transparency of the modeling process. We introduce Pop-GUIDE using fish as an example taxon and the Federal Insecticide Fungicide and Rodenticide Act (FIFRA) as a regulatory statute example.

S. Raimondo (USEPA), A. Schmolke (Waterborne), C. Accolla (University of Minnesota), J. Awkerman (USEPA), M. Etterson (USEPA), N. Galic (Syngenta), A. Moore (University of Minnesota), M. Vaugeois (University of Minnesota), P. Rueda-Cediel (University of Minnesota), N. Pollesch (USEPA), V. Forbes (University of Minnesota). Pop-GUIDE: Population modeling Guidance, Use, Interpretation, and Development for Ecological Risk Assessment. Platform 475, SETAC 2019. Toronto, Ontario, Canada.

PresentationsCrop Protection2019

Applying the Mechanistic Honey Bee Colony Model BEEHAVE to Inform Large Colony Feeding Study Design

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SETAC 2019, Platform 281
Toronto, Ontario, Canada
Session Title: Pesticides and Pollinators: Assessing Potential Risks at Colony and Population Level
Tuesday, November 5, 2019
8:40 am, Room 716B

Abstract:
In higher-tier studies aiming to assess pesticide exposure and effects to honey bees at the colony level, other factors can impact colonies and confound the analysis of potential pesticide impacts. Large colony feeding studies (LCFS) are sometimes affected by high losses of control colonies, indicating that stressors such as limited resource availability, weather, diseases and beekeeping activities may be influential. In the current project commissioned by the Pollinator Research Task Force, we assessed the study design and environmental conditions experienced by the untreated control colonies across seven LCFSs. Overwintering success in these control colonies differed considerably among the studies. In addition, the studies differed with respect to initial colony conditions, amount and timing of sugar feeding, landscape composition around study apiaries and weather. We applied the mechanistic colony model BEEHAVE to systematically assess the impact of study design and environmental conditions on control colonies. We first calibrated BEEHAVE to a subset of the studies, validated it with the remaining studies, and then used it to run simulations that changed only one variable at a time. The goal of the project was to inform study design that leads to increased likelihood of control colony overwintering success. From the simulations, the initial status of the colonies as well as the sugar feeding pattern were more important for fall colony condition than resource availability in the landscape and weather. Larger honey stores present in the colonies at study initiation, greater feeding amounts and earlier supplemental feedings (beginning in late summer to early fall) were the main factors that led to larger colony sizes and honey stores in the fall. This information can be used to inform the standardization of a study design, which in turn can increase the likelihood of overwintering survival in untreated controls and help ensure that studies are comparable. This project demonstrates how a mechanistic model can be used to inform study designs for higher-tier effects studies. Mechanistic models like BEEHAVE could further be applied to supplement higher-tier risk assessments, for instance, by extrapolating to non-tested exposure scenarios and environmental conditions and therefore potentially reducing the number of higher-tier studies.

F. Abi-Akar (Waterborne), A. Schmolke (Waterborne), C. Roy (Waterborne), N. Galic (Syngenta), S. Hinarejos (Valent).  Applying the Mechanistic Honey Bee Colony Model BEEHAVE to Inform Large Colony Feeding Study Design. Platform 281, SETAC 2019. Toronto, Ontario, Canada.

PostersCrop Protection2019

The utility of a weight-at-emergence endpoint in the 22-day larval assay for a pollinator risk assessment

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SETAC 2019, TP274
Toronto, Ontario, Canada
Session Title: Pesticides and Pollinators: Assessing Potential Risks at Colony and Population Level
Tuesday, November 5, 2019
8:00 am, Exhibit Hall

Abstract:
USEPA has identified the 22-day honey bee larval assay as a Tier 1, screening-level toxicity study for assessing pesticide risk to bees. This repeat-dose larval study is based on the Organization for Economic Co-operation and Development Guidance Document 239, and methodology provided by Schmehl et al.(2016). During this study, first instar larvae are transferred from healthy colonies to grafting cells (day 1) and treated diet is administered between days 3 and 6. Survival is assessed at multiple stages of the test: daily between days 4 and 8 for larvae; day 15 for pupae; and day 22 (emergence time) for adults. However, at the request of the USEPA, adult weight at emergence has also been included as a study endpoint. The Pollinator Research Task Force (PRTF) is conducting an endpoint evaluation to compare the sensitivity of adult weight at emergence to that of the survival endpoint in this study design. A database was developed based on anonymized study data from PRTF member companies, as well as applicable studies from the open literature. The compiled data were evaluated both empirically and statistically with regard to endpoint sensitivity. Statistically significant effects based on survival and adult weight at emergence were compared. No- and Lowest-Observed-Effect Dose (NOED and LOED) values, as well as 50% lethal and effect dose (LD50 and ED50) values were also compared between the endpoints. Coefficients of variation (CVs) were compared graphically and statistically to quantify the variability in each metric and determine significant differences. A pairing structure was also used to assess correlation, which could be graphed and statistically analyzed. This presentation outlines the methods used during this project, the results of the endpoint analyses, and concluding findings on the endpoint sensitivity comparison between survival and adult weight at emergence.

B. Sharma (FMC), D. Schmehl (Bayer), J. Collins (Waterborne), F. Abi-Akar (Waterborne), J. Jackson (Waterborne).  The utility of a weight-at-emergence endpoint in the 22-day larval assay for a pollinator risk assessment. Poster, SETAC 2019. TP274. Toronto, Ontario, Canada.

PostersCrop Protection2019

Practical Advancements in Endangered Species Risk Assessment Efficiency

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SETAC 2019, TP253
Toronto, Ontario, Canada
Session Title: Ecological Risk Assessment: What Matters and Prioritization of Resources
Tuesday, November 5, 2019
8:00 am, Exhibit Hall

Abstract:
With the release of the Environmental Protection Agency (EPA) and National Marine Fisheries Service (NMFS) organophosphate case studies for endangered species risk assessment, it became clear that the methods used in the biological evaluations and biological opinion need refinement for identifying risk to listed species and the critical habitat on which they may depend. With hundreds of pesticide registration actions annually, and more than 1,660 species listed under the Endangered Species Act, it is critical to be able to conduct a scientifically defensible risk assessment efficiently with limited time and resources. However, confidence must be high that the listed species or the critical habitat on which they depend can readily be identified as being not at risk, or at potential risk. The recently released EPA revised method for developing biological evaluations addresses some aspects of these short comings, by recognizing early in the problem formulation process that some listed species will not be exposed to a pesticide for a variety of reasons (e.g., they are extinct or extirpated; only found on federal lands). However, there are many possible additional considerations that matter, can be accounted for, and may vary on a pesticide by pesticide basis. These include label restrictions, simple spatial refinement, specific fate/behavior characteristics, listed species life history information, known and previously evaluated pesticide tolerances, and other factors. In a CropLife America funded project, these practical advancements are being identified and evaluated for use in the problem formulation process. In this presentation, the carbamate pesticide carbaryl is used to evaluate the impact of these factors on the endangered species risk assessment process, along with examples from other chemistries to more clearly show their utility.

S. Teed (Intrinsik), M. Kern (Waterborne), J. Cowles (TKI).  Practical Advancements in Endangered Species Risk Assessment Efficiency. Poster, SETAC 2019. TP253. Toronto, Ontario, Canada.