Dry Bubble (Lecanicillium)
ContaminantsAct now
Small dark necrotic lesions on caps, partly deformed mushrooms with a swollen stem base (stipe blow-out), or whole undifferentiated lumps of mushroom tissue instead of normal fruit bodies.
Likely causes
- Infection of the casing layer by the fungus Lecanicillium fungicola
- Late infection of already formed mushrooms gives only small lesions
- Spores carried by fungus gnats, tools or hands
What to do
Remove affected mushrooms and lumps without shaking them, seal them in a bag and throw them away. Wash hands and tools, avoid splashing water onto healthy mushrooms and control flies. Keep casing material clean for the next crop.
Easily confused with
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Sources
- Lecanicillium fungicola: causal agent of dry bubble disease in white-button mushroom (Molecular Plant Pathology (2010)). Symptoms range from small necrotic lesions to stipe blow-out and undifferentiated masses; late infections give small lesions, infection through the casing layer gives deformed masses; hosts include Agaricus bisporus, A. bitorquis and Pleurotus ostreatus; costs growers an estimated 2–4% of revenue.
- Attraction, Oviposition and Larval Survival of the Fungus Gnat, Lycoriella ingenua (PLoS ONE (2016)). Fungus gnat adults act as vectors of fungal pathogens in mushroom production.
Last updated: 2026-10-19