The challenge of balancing fungicide use and pollinator health

Authors: FISHER, A. - Arizona State University; DeGrandi-Hoffman, Gloria; LIAO, L.H. - University Of Illinois; TADAI, R. - Universidade Federal De Santa Catarina (UFSC); HARRISON, J. - Arizona State University

Submitted to: Advances in Insect Physiology
Publication Type: Literature Review
Publication Acceptance Date: 2/1/2023
Publication Date: 2/24/2023
Citation: Fisher II, A., Hoffman, G.D., Liao, L., Tadei, R., Harrison, J. 2023. The challenge of balancing fungicide use and pollinator health. Advances in Insect Physiology. https://doi.org/10.1016/bs.aiip.2023.01.002.
DOI: https://doi.org/10.1016/bs.aiip.2023.01.002

Interpretive Summary: Crop production has benefitted from developments in the use of natural and formulated pesticides particularly fungicides. However, numerous adverse effects of exposure to these chemical substances have been documented in a variety of organisms. Of particular concern are the negative impacts of fungicide exposure on agriculturally important insect pollinators. While the general effects of fungicides on pollinator health have garnered much interest, the potential role of these compounds has historically been poorly understood and investigated. Despite their ubiquity in the foraging environment, fungicides are deemed to be safe for pollinating insects based on low toxicity outcomes in standardized assessments by regulatory agencies. Recently, multiple studies have dispelled this traditional designation by demonstrating numerous sublethal and lethal outcomes for pollinators exposed to various fungicides. Here we provide an overview of the historical underpinnings of fungicide development and application, as well as trends in the implementation of regulatory measures. We discuss exposure routes and the prevalence of fungicides in the environment. Finally, we explore the growing body of literature revealing negative effects of fungicide exposure including the specific mechanisms by which these compounds act on non-target pollinators. We also discuss fungicide synergisms with other pesticides and the effects on pollinator immunity, metabolism, and fungicide-induced behavioral alterations. We conclude with the need for a clearer understanding of potential routes of pollinator exposure to fungicides and a broader view of sublethal effects they can have on non-target species. Field experiments coupled with population models will be essential tools for determining impacts of fungicides on pollinators, and identifying application methods that ensure crop protection and the sustainability of pollinator populations.

Technical Abstract: Human crop production has benefitted from developments in the use of natural and formulated chemical substances. However, numerous adverse effects of exposure to these chemical substances, pesticides, have been documented in a variety of organisms. Of particular concern are the negative impacts of pesticide exposure on agriculturally important insect pollinators. While the general effects of pesticides on pollinator health have garnered much interest, the potential role of certain pesticide classes has historically been poorly understood and investigated. Despite their ubiquity in the foraging environment, fungicides were traditionally deemed to be safe for pollinating insects based on low toxicity outcomes in standardized assessments by regulatory agencies. Recently, multiple studies have dispelled this traditional designation by demonstrating numerous sublethal and lethal outcomes for pollinators exposed to various fungicides. Here we provide an overview of the historical underpinnings of fungicide development and application, as well as trends in the implementation of regulatory measures. We discuss exposure routes and the prevalence of fungicides in the environment. Finally, we explore the growing body of literature revealing negative effects of exposure including the specific mechanisms by which fungicides act on non-target pollinators, fungicide synergisms with other pesticide classes, pests, pathogens and phytochemicals, and fungicide-induced behavioral alterations.