Comparison of the effect of insecticides on bumble bees (Bombus impatiens) and mosquitoes (Aedes aegypti and Culex quinquefasciatus) by standard mosquito research methods

Authors: McGregor, Bethany; GIORDANO, BRYAN - University Of Florida; RUNKEL, ALFRED - University Of Florida; NIGG, HERBERT - Magnetar Designs; NIGG, H. LEE - Magnetar Designs; BURKETT-CADENA, NATHAN - University Of Florida

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2020
Publication Date: 12/25/2020
Citation: McGregor, B.L., Giordano, B.V., Runkel, A.E., Nigg, H.N., Nigg, H., Burkett-Cadena, N.D. 2020. Comparison of the effect of insecticides on bumble bees (Bombus impatiens) and mosquitoes (Aedes aegypti and Culex quinquefasciatus) by standard mosquito research methods. Journal of Economic Entomology. 114(1):24-32. https://doi.org/10.1093/jee/toaa282.
DOI: https://doi.org/10.1093/jee/toaa282

Interpretive Summary: Mosquito control districts in the United States are limited to two main classes of pesticides, organophosphates and pyrethroids, to control adult mosquito pests and disease vectors. While the effect of these pesticides on European honeybees has been investigated, effects on native North American pollinators need additional research. The purpose of this study was to investigate non-target effects of these pesticides on Bombus impatiens, a native North American bumble bee species, through field and laboratory pesticide application assays. Field assays were also conducted on additional wild collected non-target insects. Laboratory and field studies indicated variable responses of Bombus impatiens, mosquitoes, and wild collected non-target organisms to the two pesticides studied. Our results demonstrate that common mosquito control adulticides cause varying degrees of non-target mortality, indicating that some pesticides may be more appropriate than others for use during periods of non-target activity. Further studies are needed to develop pollinator-friendly pesticide application regimens capable of controlling nuisance and vector mosquitoes.

Technical Abstract: Mosquito control districts in the United States are limited to two main classes of adulticides, pyrethroids and organophosphates, to control pest and vector mosquito species. Two adulticides used to control domestic mosquitoes are Fyfanon EW (malathion, organophosphate) and DeltaGard (deltamethrin, pyrethroid). While the effect of these pesticides on European honeybees (Apis mellifera L., Hymenoptera:Apidae) has been investigated, effects on native pollinators need additional research. The purpose of this study was to investigate the acute non-target effects of these pesticides on Bombus impatiens Cresson (Hymenoptera: Apidae), a native North American bumble bee species, through field and laboratory assays. Field assays were also conducted on additional wild collected non-target organisms. Bombus impatiens was found to be resistant to Fyfanon EW but sensitive to DeltaGard in laboratory bottle bioassays. In the field, we observed acute effects of DeltaGard on mosquitoes and non-target organisms at 25 m and 75 m distance from a truck-mounted ULV fogger. All Culicidae, Diachlorus ferrugatus Fabricius (Diptera: Tabanidae), Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae), and Plecia nearctica Hardy (Diptera: Bibionidae) exposed to DeltaGard at the 25 m spray line were immobile 24-hours post-exposure. Bombus impatiens displayed moderate mortality to DeltaGard at 24-hours post-exposure, although there was no significant treatment effect for B. impatiens. This study indicated that common mosquito control adulticides do cause non-target mortality to native pollinators. Further studies are needed to develop pollinator friendly pesticide application regimens that improve potential outcomes for pollinators while also permitting pesticide applications targeting pest and vector mosquitoes that threaten human populations.