The U.S. Environmental Protection Agency (EPA) has given registration to Norroa, GreenLight Biosciences’ nature-based treatment specifically designed to combat varroa mites.

Norroa’s active ingredient, vadescana, leverages RNA interference (RNAi), a natural biological process that precisely targets varroa mites and ultimately stops their reproduction. The nucleic acids in the product are found in nature, and vadescana breaks down quickly in the environment.

GreenLight Bio said that rigorous, replicated field trials conducted across multiple U.S. regions demonstrated extended mite control of up to 18 weeks, resulting in improved overall colony health. Researchers confirmed Norroa’s performance against varroa mites and its safety for honey bees, humans, other insects, and the environment.

“Beekeepers have been urgently seeking alternatives as existing miticides lose their potency,” said Mark Singleton, chief commercial officer and general manager at GreenLight Bio. “Norroa represents a breakthrough in honey bee protection from varroa mites, offering beekeepers an effective and easy-to-use tool that keeps mite populations down for up to 18 weeks, which is substantially longer than the existing products on the market. Norroa can be applied at any temperature, provided it’s safe to open the hive, and has no negative impacts on brood, workers, or queens.”

A February 2025 U.S. survey of beekeepers revealed honey bee colony losses across the United States at 1.7 million, with commercial operations reporting an average loss of 62 percent between June 2024 and February 2025. USDA researchers contend the trend is related to the declining efficacy of existing miticides as Varroa mites have developed resistance to chemical treatments.

Norroa will be available for sale exclusively through Mann Lake Ltd. and its authorized dealer network.

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