New Hope for Varroa Control: RNAi Shows Promise in the Field

A breakthrough in the fight against Varroa mites has just been published, and every beekeeper should take note. For the first time, a field trial has demonstrated that RNA interference (RNAi) technology—previously tested only in labs—can effectively reduce Varroa mite infestations under real-world beekeeping conditions.

The study, led by Francesca Bortolin and her team and published in Parasites & Vectors (2025), tested a blend of RNA molecules (called dsRNA) that target essential genes in Varroa destructor. When bees were fed a sugar syrup mixed with these molecules, mites that fed on the bees showed significantly reduced gene activity and survival.

Why It Matters

• Proven in the field: This is the first successful demonstration outside the lab.

• Mite levels dropped by up to 42% in treated hives compared to controls.

• No harm to bees: The treatment didn’t affect adult bee survival or colony strength.

• Beekeeper-friendly: Participants reported it was easy to apply and didn’t disrupt production.

• Sustainable: RNAi offers a targeted, residue-free alternative to synthetic chemicals, aligning with global efforts to reduce pesticide use.

What’s RNAi?

RNA interference is a natural process in cells that can be harnessed to “turn off” specific genes. In this case, scientists designed dsRNA to silence three key Varroa genes involved in metabolism, ion balance, and moulting. The mites pick up the dsRNA after feeding on bees, leading to reduced survival or reproduction.

The Bigger Picture

RNAi could offer a game-changing tool with the increasing chemical resistance in Varroa and the concerns about residues in wax and honey. Unlike most treatments that only affect mites outside the brood, RNAi may also reach mites during reproduction via the bees' internal food-sharing system (trophallaxis and jelly).

The Takeaway for Beekeepers

This study is still early days, but it's a strong proof of concept. As this technology matures, it could become a core part of integrated Varroa management, especially in autumn when traditional treatments are least effective. If you're a beekeeper concerned about long-term sustainability and Varroa resistance, this is one development to watch closely.

Full study here: Parasites & Vectors, 2025