Can a Mushroom Protect Bees from one of Their Deadliest Parasite?

The Varroa destructor mite is one of the most damaging threats to global honeybee populations. These parasitic mites feed on bee fat bodies, suppress immune function, and spread lethal viruses throughout the colony. Conventional treatments often rely on synthetic acaricides, which can lead to resistance and chemical residues in hives. But a new study suggests that help might come from an unexpected ally: Fomes fomentarius, a wood-rotting mushroom with a long history of medicinal use.

A Fungal Biocontrol Alternative

In a field trial conducted in Düzce, Türkiye, researchers tested three different preparations of Fomes fomentarius to control Varroa destructor: smoke fumigation, a liquid dribble solution, and a gel-based formulation. All three significantly reduced mite populations after two weeks, with the gel proving most effective—achieving an average mite mortality rate of 72.1%. Importantly, no adverse effects on brood health or colony size were observed.

The study, led by Mustafa Güneşdoğdu and colleagues, adds to a growing body of research exploring the antimicrobial and antiviral properties of fungal metabolites. While Fomes fomentarius has been traditionally used as tinder and in folk remedies, it also produces bioactive compounds with acaricidal, antifungal, and immunomodulatory effects. Its application in beekeeping could provide a residue-free, resistance-resistant tool in integrated pest management.

Beyond the Mite: Implications for Colony Health

The researchers noted more than just a decline in mite counts. Colonies treated with Fomes fomentarius showed greater brood vitality, better adult bee activity, and more consistent hive temperatures—suggesting potential immunological or metabolic benefits beyond direct mite control.

This aligns with earlier work from Paul Stamets and researchers at Washington State University, who found that extracts from Fomes fomentarius and Ganoderma resinaceum reduced viral loads (including deformed wing virus and Lake Sinai virus) in infected bees. Their 2018 study in Scientific Reports suggested fungal polysaccharides could modulate bee immunity and improve resistance to viral infection.

Why It Matters

With colony losses remaining stubbornly high—reaching 48% in the US during the 2022–2023 winter season—solutions that don’t introduce further chemical stress are urgently needed. Fungal-based treatments like this offer a sustainable, low-cost approach that could be scaled by beekeepers globally.

As commercial beekeeping operations face mounting pressure from climate change, habitat loss, and disease, tools that reduce dependency on synthetic chemicals are becoming essential. Fomes fomentarius may not be a silver bullet, but it shows real promise as part of a broader toolkit to protect pollinator health.

Read more:

Güneşdoğdu et al. (2024). "Biocontrol effect of Fomes fomentarius mushroom against Varroa destructor." Available at: ResearchGate