Mold

Dry Bubble Disease

A fungal disease that attacks mushroom fruit bodies, causing deformed, lumpy masses instead of normal mushrooms. Named "dry bubble" because infected mushrooms form round, dry, undifferentiated masses of tissue. Major problem in commercial Agaricus (button mushroom) cultivation.

Verticillium fungicolaHigh riskDiscard the batch

Dry Bubble Disease in a mushroom grow (illustration) — Reference illustration

What does Dry Bubble Disease look like?

Deformed, lumpy, round mushroom masses instead of normal caps and stems. Brown spots on caps. Tilting or leaning mushrooms. Gray fuzzy growth on affected areas.

Color: Brown
Texture: Spotted, deformed
Smell: None initially
Growth speed: Moderate

Why does Dry Bubble Disease show up?

Contaminated casing soil, fly vectors, splashing water between blocks, poor hygiene, contaminated tools.

What do I do if I find Dry Bubble Disease in my grow?

Remove and destroy affected mushrooms and surrounding substrate.
Salt the affected area to prevent spore spread.
Increase hygiene protocols.
Consider reducing humidity temporarily.
Treat remaining crop with appropriate fungicide if applicable.

How do I prevent Dry Bubble Disease?

Use pasteurized casing layer.
Maintain hygiene in fruiting room.
Control flies (vectors).
Dip tools in disinfectant between blocks.
Avoid splashing water between blocks.

At which stage does Dry Bubble Disease appear?

Stage	Risk	What happens	How to prevent it
Preparation	Low	Can be present in contaminated casing materials.	Pasteurize casing layer properly.
Inoculation	No risk	—	—
Colonization	Low	Can be introduced with casing layer.	Use clean casing materials.
Fruiting	High	Disease manifests during fruiting — deformed mushrooms, brown spots.	Maintain hygiene. Control flies. Dip tools in disinfectant. Avoid water splash.
Harvest	Moderate	Can spread during harvesting if tools are contaminated.	Disinfect hands and tools between blocks.