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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #368900
Research Project: New Technologies and Strategies to Manage the Changing Pest Complex on Temperate Fruit Trees

Location: Temperate Tree Fruit and Vegetable Research

Title: Not all predators are equal: miticide non-target effects and differential selectivity

Author
item BERGERON, PAUL - Washington State University
item Schmidt, Rebecca

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2020
Publication Date: 5/6/2020
Citation: Bergeron, P., Schmidt-Jeffris, R.A. 2020. Not all predators are equal: miticide non-target effects and differential selectivity. Pest Management Science. 76(6):2170-2179. https://doi.org/10.1002/ps.5754.
DOI: https://doi.org/10.1002/ps.5754

Interpretive Summary: Management of pests in agricultural systems frequently relies on predators of those pests, or biological control. In conventional agriculture, biological control must be integrated with chemical control to be successful. This means that growers should choose pesticides that are capable of controlling the pest, but cause minimal harm to that pest's predators. Researchers at the USDA-ARS in Wapato, in collaboration with Washington State University, examined the effects of miticides on an important pest (twospotted spider mite) and four different populations of spider mite predators. All pesticides tested had harmful effects on at least one predator population. The pesticides cyflumetofen and acequinocyl were the most effective at controlling spider mites while simultaneously causing the least amount of harm to the predators. This information will allow growers to select pesticides minimally harmful to spider mite predators, reducing pesticide use by promoting biological control, which in turn will result in grower savings and decreased environmental contamination by pesticides.

Technical Abstract: Biological control in conventional agroecosystems involves the integration of chemical and conservation tactics, requiring knowledge of pesticide non-target effects on key natural enemies. Even for natural enemy groups such as predatory mites (Acari: Phytoseiidae), where pesticide non-target effects have been thoroughly examined, there may be significant differences in species susceptibility to specific active ingredients, including newer, selective products. Using bioassays, we examined lethal (female mortality) and sublethal effects (fecundity, egg hatch, production of larvae) of ten miticides on a spider mite pest (Tetranychus urticae) and three insectary-purchased predatory mites (Phytoseiulus persimilis, Neoseiulus californicus, and Neoseiulus fallacis) commonly used for its management. Susceptibility of field-collected and insectary-reared populations of P. persimilis was also compared. Cumulative impacts on production of larvae by treated female predators and spider mites were compared to create a metric that simultaneously accounted for miticide efficacy and selectivity. All products, including those considered selective (cyflumetofen, bifenazate, acequinocyl) had non-target effects on at least one species of predator tested. Bifenthrin was the least selective, causing acute toxicity to all predators and having little efficacy against T. urticae. Cyflumetofen and acequinocyl were the most selectively favorable. P. persimilis populations were similar in which miticides they were sensitive to, although the insectary-purchased population was generally more sensitive. This work emphasizes that there is high variability in selectivity between species, highlighting the need to examine key natural enemies individually when creating management programs.