New Treatments Aim to Help Beekeepers Battle Mite Infestations

Researchers find combining amitraz pesticide with inhibiting compound can increase effectiveness against resistant varroa mites.

Published on Feb. 27, 2026

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Researchers from the USDA's Agricultural Research Service (ARS) and the University of California, Davis, have discovered a new approach to help beekeepers protect their honeybee colonies from destructive varroa mites. The researchers found that combining the widely used mite-killing pesticide amitraz with an inhibiting compound can increase the pesticide's toxicity and effectiveness, even against amitraz-resistant mites.

Why it matters

Varroa mites are a major threat to honeybee colonies across the United States, causing significant damage and spreading deadly viruses. As the mites become increasingly resistant to common pesticides like amitraz, beekeepers need new tools and strategies to control infestations and protect their hives. This research offers a promising solution that could help turn the tide in the ongoing battle against varroa mites.

The details

In their study, the researchers found that combining amitraz with an inhibiting compound that prevents the mites from tolerating the pesticide can increase amitraz's killing power by up to 50%. This approach was effective even against amitraz-resistant mites, which have become a growing problem for beekeepers as the mites evolve to withstand the pesticide. The researchers say this new synergistic treatment could help beekeepers save time and money by reducing the need for additional treatments and lowering the selection pressure on mite populations.

  • The study was published on February 16, 2026 in the Journal of Apicultural Research.

The players

USDA's Agricultural Research Service (ARS)

A federal research agency that conducts scientific investigations to support American agriculture.

University of California, Davis

A public research university located in Davis, California that is known for its expertise in agriculture and environmental sciences.

Julia Fine

A research entomologist at the USDA's Pollinator Health Research Laboratory in Davis, California and a co-leading author of the study.

Sascha Nicklisch

An assistant professor in the UC Davis Environmental Toxicology department and a co-leading author of the study.

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What they’re saying

“This compound inhibits a naturally occurring process that prevents certain chemicals, like pesticides, from accumulating inside cells. If a chemical toxicant can't reach a high enough concentration in a cell, it won't have a toxic effect in the organism. Previously, we didn't know if this process was part of how varroa tolerate amitraz exposure.”

— Julia Fine, Research Entomologist, USDA Pollinator Health Research Laboratory (Journal of Apicultural Research)

“Our study shows that we can increase amitraz's killing power by 50% when used in combination with another compound - a synergist - that weakens the mite but doesn't cause harm to bees. This research aims to provide beekeepers with practical tools and strategies that they can implement to effectively control varroa mites, especially since these mites become increasingly resistant to our limited arsenal of bee-safe pesticides like amitraz.”

— Sascha Nicklisch, Assistant Professor, UC Davis Environmental Toxicology (Journal of Apicultural Research)

What’s next

The researchers say the next step is to develop synergists that specifically inhibit the mite's ability to tolerate amitraz without affecting honeybees, in order to provide beekeepers with an even more effective tool for controlling varroa infestations.

The takeaway

This research offers a promising new approach to help beekeepers combat the growing threat of varroa mites, which have become increasingly resistant to common pesticides. By combining amitraz with an inhibiting compound, the researchers were able to significantly boost the pesticide's effectiveness, providing a potential new weapon in the ongoing battle to protect honeybee colonies.