Miticide non-target effects
on predatory mites in walnuts
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This database compares pesticides currently registered in California for use to control web-spinning spider mites in walnuts based on their effects on Phytoseiids, which are the most common family of predatory mites that provide biological control of pest mites.
This database is based on the paper, “Meta-analysis and review of pesticide non-target effects on phytoseiids, key biological control agents,” written by Schmidt-Jeffris, et al. in 2021.
What is this?
In integrated pest management, pesticides should be used as needed and with consideration for its effects on natural enemy populations. Using pesticides that are harmful to natural enemies can cause secondary outbreaks of non-target pests.
Predatory mites, specifically Phytoseiids, are one of the main natural enemies of the web-spinning spider mite, and one of the most studied. The paper Schmidt-Jeffris, et al. looked at 154 published papers examining the impact of pesticides on lethal and sublethal effects on predatory mites in laboratory trials. We assigned a rating for each active ingredient’s effects on predatory mite adults, juveniles, fecundity, and egg hatch.
Western predatory mites, Galendromus (=Metaseiulus) occidentalis (top and bottom), and a twospotted spider mite, Tetranychus urticae (center), and its eggs.
(Used with permission from University of California Statewide IPM Program, J. K. Clark, photographer.)
On desktop, the Search button is at the top right corner.
On mobile, the Search button is below the title “Miticide database.”
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Click the search button in the top right corner of the database and type in the trade name you are looking for (ex. “Acramite”). It will highlight the trade name and its corresponding active chemical ingredient, and the effect rating it has on predatory mites.
The active chemical ingredients are grouped by the “summary rating,” which is the most harmful rating in any of the four life stages.
This database is based on the paper, “Meta-analysis and review of pesticide non-target effects on phytoseiids, key biological control agents,” written by Schmidt-Jeffris, et al. in 2021. The database was compiled by Moet Takata, with support from Hanna Kahl, Gisel De La Cerda, and Elliott Ge. It is funded by the California Walnut Board and the California Department of Agriculture’s Biologically Integrated Farming Systems Program.