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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #417515
Research Project: Integrated Approach to Manage the Pest Complex on Temperate Tree Fruits

Location: Temperate Tree Fruit and Vegetable Research

Title: Non-target effects of insecticides and herbicides on earwigs

Author
item HANEL, ALDO - Washington State University
item NOTTINGHAM, LOUIS - Washington State University
item NORTHFIELD, TOBIN - Washington State University
item Schmidt-Jeffris, Rebecca

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2025
Publication Date: 2/4/2025
Citation: Hanel, A., Nottingham, L., Northfield, T., Schmidt-Jeffris, R.A. 2025. Non-target effects of insecticides and herbicides on earwigs. Journal of Economic Entomology. https://doi.org/10.1093/jee/toaf012.
DOI: https://doi.org/10.1093/jee/toaf012

Interpretive Summary: Earwigs are important predators of many tree fruit pests. Conservation of earwigs requires knowledge of possible non-target effects of pesticides on these predators. USDA researchers in Wapato, WA in collaboration with Washington State University researchers investigated the effects of eight insecticides and seven herbicides on earwig mortality, feeding rate on pest aphids, and movement. The herbicides paraquat and glufosinate caused the majority of earwigs to die within 48 hours. Most herbicides and some insecticides reduced earwig feeding rates. This information was used to provide tree fruit growers with updated recommendations for spray programs that conserve earwigs in their orchards.

Technical Abstract: Conservation biological control in agriculture primarily relies on avoiding pesticides that may harm key natural enemies. In temperate tree fruit crops, the European earwig, Forficula auricularia (L.) has only recently become appreciated as an important predator of economic pests, particularly woolly aphids and pear psylla. Therefore, the non-target effects of orchard pesticides on earwigs are largely understudied. This is particularly true for herbicides, which earwigs are likely to be exposed to due to their foraging behavior moving between the canopy and the ground cover. We tested residues of formulated pesticides (8 insecticides and 7 herbicides) commonly used in tree fruit crops for lethal and sublethal (movement, predation rate) effects on adult female earwigs. Two herbicides, paraquat and glufosinate, and one insecticide, spinetoram, were acutely toxic to earwigs within 72 h. No tested pesticides altered earwigs’ movement or resting behavior compared to the control. The insecticides spinosad and cyantraniliprole and the herbicides 2,4-D, glufosinate, halosulfuron, rimsulfuron, and oxyfluorfen reduced earwig predation on green peach aphids. Therefore, these pesticides may reduce earwig predation on pests in orchards. Our results suggest that some pesticides are of greater risk, and thus, should be carefully considered or better timed when used in tree fruit orchards where earwigs are considered for conservation or augmentative biological control.