Location: Pollinator Health in Southern Crop Ecosystems Research
2022 Annual Report
Objectives
1. Determine pesticide risks to honey bees, both by laboratory assays and field studies in southern cropping systems, including the mode of action of insecticides on bee pollinators and interactions with other pesticides.
2. Develop IPM systems to mitigate the effects of pesticides on bees in these systems.
3. Determine the role of non-crop vegetation in the health of bees in these systems, with a focus on enhancing bee forage habitat.
4. Conduct studies on native bee diversity and biology in southern cropping systems to improve the use of local bee species for pollination of regional crops such as squash and berries.
5. Conduct studies on aerial and ground application of pesticides, examining drift patterns and design equipment and spray adjuvants/dispensers that uses precision application to minimize off-target application onto adjacent non-cropping areas associated with bee habitat.
Approach
This new Research Unit will focus on how to improve both native and honey bee health as well as improving natural habitat and minimizing risk to stressors including pesticides and pests in a way that is beneficial to both beekeepers and farmers. The southern United States has traditionally been an area of high row crop agriculture with often high pest pressure than routinely needs synthetic pesticides to keep populations below economic injury levels. These areas are only now seeing the influx of commercial beekeepers that traditionally have been located in other areas of the U.S. Therefore, there is a need to determine ways to increase the health of both managed honey bees as well as native bees that are often needed for pollination services for farmers as well as producing honey for the commercial beekeeper. In addition, there is a lack of knowledge in the overall ecology of non-crop forage (i.e. weeds and native vegetation) to provide suitable habitat for bees as well as determining the risk of certain pesticides on bee health. Finding answers on which strategies increase bee health while being feasible and economical both to the farmer and commercial beekeeper is of the highest priority. Reducing pollinator losses by improving bee health is essential for consistently providing adequate bee populations for crop pollination and ensuring the productivity of U.S. crops that require bee pollination. Identification of particularly damaging chemical pesticides as well as improved application strategies that minimize impact on non-target organisms, such as bees, will inform exposure risks that may be mitigated. Conserving the diversity of non-Apis bees, including bumble bees, alfalfa leafcutter bees, and blue orchard bees, is essential for pollinating certain agricultural crops in addition to hundreds of species of native plants that can be forage for managed honey bees. Progress in NP305 will be accelerated by the information provided by this project. All information generated will be made available through various research publications outlets including outreach using University extension personnel. In addition, the new Unit will collaborate extensively with external partners including landgrant Universities and other federal agencies through outgoing NACAs and interagency agreements.
Progress Report
In collaboration with other USDA ARS researchers, experiments to determine if agricultural conservation management can have bottom-up effects for the resources that plants produce for pollinators have been initiated and a first season of data collected. Additional experiments caging honey bees to assess the interactions of nutrition and pesticides were initiated in collaboration with other unit scientists. An interagency agreement, "Establishing a Chemical Database for Nectar and Honey Analysis", was initiated with the Office of the Chief Scientist. Honey bee pollen samples are also being collected in the Mississippi and processed to determine what plants honey bees are visiting for pollen throughout the year.
Although best practices are available, opportunities still exist to mitigate off-target pesticide drift. Experiments were begun to identify opportunities to mitigate drift from ground-based preemergent herbicide applications. Seven herbicide applications were tested in commercial corn, soybean, and cotton production systems. Drift data were collected using water sensitive cards and the droplet spectrum analyzed. Drift volumes and distances were estimated for each experiment. Data were collected on wind speed, boom length, spray height, tractor speed, and chemical application rate were used as explanatory variables of drift volume and drift distance. Regression analyses were carried out between drift volume, drift distance, and explanatory variables. Preliminary results show a three- to four-fold reduction in drift using a hooded sprayer or spraying in calm weather. Boom length and spray height appear to be the dominant parameters affecting drift volume and drift distance, respectively. Results suggest that we can estimate drift volume and drift distance reliably using a combination of variables.
We continued to make collections and identify native bees from a variety of habitats across the southeastern United States. Samples were collected with a combination of collection techniques including modified pan traps (bee bowls), malaise traps, vane traps, and net sampling. All specimens have been cleaned, pinned, mounted, and entered into a database. Common species have been completely identified and ARS scientists are working with taxonomists to identify rare taxa. Specimens of species new to the state or of significance have been deposited with regional, national, and international entomological collections. This baseline information is being used to examine potential impacts of local agricultural production practices on these insects and compare with production practices and pollinator communities in other regions.
Preliminary findings from a single year large cage trial using three varieties of soybeans, each in a different maturity group. These varieties were each replicated three times in each cage, and each set of three cages received a pollinator treatment (honey bees only, no bees, or access by all bees). Soybean samples have been analyzed by using several metrics, and bee specimens are in the final processes of being identified.
Multiple species of native bees from the southeastern U.S. have been collected and are preserved at -80C toward this project and the agency’s larger “Beenome100” project. The beenome project aims to sequence the genomes of 100 native bees in collaboration with university colleagues from the University of Illinois and other USDA ARS researchers. Several of the bee species collected from Mississippi have completed both HiFi and HiC sequencing, and other locally collected species are in the pipeline.
Accomplishments
1. The health of pollinators, both wild and managed, is of national and international concern. A new ARS research unit focused on Pollinator Health was established in Stoneville, Mississippi, during 2020, but most of the scientific and support positions were filled this year. New research projects focusing on pollinator health in southern agroecosystems and examining the interactions between bees, agricultural production, and the surrounding landscape are underway by ARS researchers in Stoneville, Mississippi.
Review Publications
Parys, K.A., Davis, K.A., James, S., Davis, J.B., Tyler, H.L., Griswold, T.L. 2022. First report of a gynandromorph of Florilegus condignus (Cresson, 1878) (Hymenoptera: Apidae), with notes on phenology and abundance. Journal of Hymenoptera Research. https://doi.org/10.3897/jhr.89.75857.
Demares, F.J., Schmehl, D., Bloomquist, J.R., Cabrera, A.R., Huang, Z.Y., Lau, P.W., Ranel, J., Sullivan, J., Xie, X., Ellis, J.D. 2022. Honey bee (Apis mellifera) exposure to pesticide residues in nectar and pollen in urban and suburban environments from four regions of the United States. Environmental Toxicology and Chemistry. https://doi.org/10.1002/etc.5298.
Lau, P.W., Lesne, P., Grebenok, R.J., Rangel, J., Behmer, S.T. 2022. Assessing pollen nutrient content: a unifying approach for the study of nutritional ecology. Philosophical Transactions of the Royal Society B. https://doi.org/10.6084/m9.figshare.c.5923123.
Okosun, O.O., Reddy, G.V. 2021. Holistic management of pollinators and pests: Integrating semiochemicals with on-farm pesticides. Annals of the Entomological Society of America. 114:1-13. https://doi.org/10.1093/aesa/saab035.
Wang, Y., Zhu, Y., Li, W., Yao, J., Reddy, G.V., Lv, L. 2021. Binary and ternary toxicological interactions of clothianidin and eight commonly used pesticides on honey bees (Apis mellifera). Ecotoxicology and Environmental Safety. 223:112563. https://doi.org/10.1016/j.ecoenv.2021.112563.
Lau, P.W., Payne, A.N., Khan, O., Buchman, M.B., Rangel, J. 2022. The impact of COVID-19 on beekeepers in Texas and Louisiana. Journal of Apicultural Research. 61(3):309-314. https://doi.org/10.1080/00218839.2022.2051333.
Kannan, N., Venkataraman, K., Stroebel, J., Taylor, L. 2022. Investigating the causes of reduced dissolved oxygen concentrations in Kickapoo Creek, TX. Environmental Monitoring and Assessment. 194:574. https://doi.org/10.1007/s10661-022-10209-2.
