Cobweb Mold (Dactylium)
ContaminantsAct soon
Wispy, grey, fast-spreading fuzz that grows OVER pins and substrate — looser and greyer than healthy mycelium, doubling in hours.
Likely causes
- Humidity too high with stagnant air
- Poor fresh-air exchange
What to do
Caught early, spot-treat (3% hydrogen peroxide) and raise fresh air; if it's spreading over the fruit, bin the block.
Easily confused with
Not sure?
Walk through the troubleshooting guide, ask the AI Grow Consultant, or check the conditions your species needs on its species page.
Sources
- Fungicide Sensitivity and Characterization of Cobweb Disease on a Pleurotus eryngii Mushroom Crop Caused by Cladobotryum mycophilum (Plant Pathology Journal (2014)). Cobweb-like growth over the mushroom surface that produced spores within 3–4 days, turning the surface pale brown or yellow and later dark brown and rancid; cobweb disease caused crop losses of up to 40% in the UK and Ireland in the 1990s.
Last updated: 2026-10-19