False Truffle (Diehliomyces)
ContaminantsAct now
A fungal contaminant of mushroom compost named for the lumpy, truffle-like masses it forms; the mushroom mycelium fails in the affected compost and yields collapse.
Likely causes
- Badly composted or poorly pasteurised compost
- Compost brought in from another farm
- Poor hygiene and poor cleaning between crops
What to do
Treat it as a severe compost-quality problem: do not reuse the affected compost, remove it from the growing area and rebuild the compost process with a full pasteurisation phase. Clean the room before the next crop.
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Sources
- Mushroom Growers' Handbook 2: Shiitake Cultivation, chapter 'Agaricus blazei cultivation as a livelihood in Brazil' (Spanish edition) (MushWorld (2005), Spanish translation by CERZOS (UNS-CONICET)). False truffle (Diehliomyces) was the most serious fungal disease diagnosed in Santa Catarina in 1999, responsible for losses of 50–80% of production on several farms; the source was badly composted substrate introduced from another state; fungal contamination is described as an indicator of low-quality compost, and lack of casing disinfection and poor hygiene lead to parasitic fungi.
Last updated: 2026-10-19