Skip to main content
ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Research Project #432300

Research Project: Modeling Honey Bee Exposure to Pesticides in Pollination Dependent Crops of California

Location: Invasive Species and Pollinator Health

Project Number: 2030-21000-055-005-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jul 16, 2018
End Date: Jul 11, 2023

1) Develop spatially explicit indices (maps) that predict potential pesticide exposure to bees in agricultural landscapes for at least 3 representative counties of the Central Valley by the end of 2020. Maps will report relative risk values based on integrating existing models of bee foraging with spatially and temporally explicit pesticide application data from California’s Pesticide Use Report (PUR) database weighed by toxicity. 2) Validate the predictive maps of pesticide exposure for bees using data on pesticide residues in pollen collected from replicate honey bee colonies placed at 20 landscapes across the target Central Valley counties by the end of 2020. 3) In collaboration with stakeholders, use maps of potential exposure risk for bees and the models that underlie them to help growers, beekeepers, extension specialists, land managers, and policy makers identify locations and target the sources that present challenges for bees.

The approach includes the use of existing models of foraging bees based on land use maps and floral resources and add pesticide application data weighted by environmental persistence and toxicity to bees. Cooperators will use pesticide application data at section- and parcel-level from the PUR database and county records. Lethal Dose 50 (LD50) values for honey bees have already been collected in databases in two independent projects. These provide bee toxicity inputs. Team members have previously used PUR data to examine environmental impacts and worked with base foraging models for bees. Their familiarity with these data will greatly facilitate the flow of the project and help to avoid potential pitfalls. The specific approaches used to meet the objectives include developing field validated maps of potential pesticide exposure risk to bees across agricultural lands for three counties (Yolo, Solano, Kern) by the end of 2020. By basing these maps on CDPR–Pesticide Use Reports database inputs they can be updated over time to incorporate variability in potential risk among seasons and years, and also identify persistent hot-spots. Maps will be used collaboratively with extension specialists, growers, commodity boards, and state agencies to guide coordinated reduced risk pesticide practices for the major pollinator dependent tree fruit crops in the region (e.g., almond, plum) over the next 2-5 years. Publicly available maps will also provide transparency about areas of greatest potential risk for beekeepers and specialty crop grower-partners, reducing uncertainty and conflict related to pesticide application.