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ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #315923
Title: Spray toxicity and risk potential of 42 commonly used formulations of row crop pesticides to adult honey bees (Hymenoptera:Apidae)

Author
item Zhu, Yu Cheng
item Adamczyk, John
item Rinderer, Thomas
item Yao, Jianxiu
item Danka, Robert
item Luttrell, Randall
item GORE, JEFF - Delta Research & Extension Center

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2015
Publication Date: 9/6/2015
Citation: Zhu, Y., Adamczyk Jr, J.J., Rinderer, T.E., Yao, J., Danka, R.G., Luttrell, R.G., Gore, J. 2015. Spray toxicity and risk potential of 42 commonly used formulations of row crop pesticides to adult honey bees (Hymenoptera:Apidae). Journal of Economic Entomology. 108(6):2640-2647. doi:10.1093/jee/tov269.

Interpretive Summary: To combat an increasing abundance of sucking insect pests, more than 40 pesticides are currently recommended and frequently used as foliar sprays on row crops, especially cotton. Foraging honey bees may be killed when they are directly exposed to foliar sprays, or they may take contaminated pollen back to hives that may be toxic to other adult bees and larvae. To assess acute toxicity against the honey bee, we used a modified spray tower to simulate field spray conditions to include direct whole-body exposure, inhalation, and continuing tarsal contact and oral licking after a field spray. A total of 42 formulated pesticides, including one herbicide and one fungicide, were assayed for acute spray toxicity to 4-6-day old worker bees. Results showed significantly variable toxicities among pesticides with median lethal concentration (LC50) ranging from 25 to thousands of mg/L. Further risk assessment using the field application concentration to LC1 (pesticide concentration that incurs 1% of honey bee mortality) or LC99 (pesticide concentration that incurs 99% of honey bee mortality) ratios revealed the risk potential of the 42 pesticides. Three chemicals killed less than 1% of the worker bees, including the herbicide, a miticide, and a neonicotinoid. Twenty-six insecticides killed more than 99% of the bees, including commonly used organophosphates and neonicotinoids. The remainder of the 13 chemicals killed from 1-99% of the bees at field application rates. This study reveals a realistic acute toxicity of 42 commonly used foliar pesticides. The information is valuable for guiding insecticide selection to minimize direct killing of foraging honey, while maintaining effective control of field crop pests.

Technical Abstract: To combat an increasing abundance of sucking insect pests, more than 40 pesticides are currently recommended and frequently used as foliar sprays on row crops, especially cotton. Foraging honey bees may be killed when they are directly exposed to foliar sprays, or they may take contaminated pollen back to hives that maybe toxic to other adult bees and larvae. To assess acute toxicity against the honey bee, we used a modified spray tower to simulate field spray conditions to include direct whole-body exposure, inhalation, and continuing tarsal contact and oral licking after a field spray. A total of 42 formulated pesticides, including one herbicide and one fungicide, were assayed for acute spray toxicity to 4-6-day old workers. Results showed significantly variable toxicities among pesticides with LC50s ranging from 25 to thousands of mg/L. Further risk assessment using the field application concentration to LC1 or LC99 ratios revealed the risk potential of the 42 pesticides. Three pesticides killed less than 1% of the worker bees, including the herbicide, a miticide, and a neonicotinoid. Twenty-six insecticides killed more than 99% of the bees, including commonly used organophosphates and neonicotinoids. The remainder of the 13 chemicals killed from 1-99% of the bees at field application rates. This study reveals a realistic acute toxicity of 42 commonly used foliar pesticides. The information is valuable for guiding insecticide selection to minimize direct killing of foraging honey, while maintaining effective control of field crop pests.