Symptom Identification and Control Methods for Visible Mycelial Diseases in Button Mushrooms (Agaricus bisporus)

Visible mycelial disease in button mushrooms (Agaricus bisporus) generally refers to a class of fungal diseases that produce obvious symptoms visible to the naked eye during button mushroom cultivation, occurring mainly on the casing layer, the substrate surface and the fruiting bodies. Common production problems such as wet bubble disease and dry bubble disease can generally be included in this category. Once such diseases show obvious mycelial patches or deformed mushrooms, it indicates that the pathogen has already multiplied considerably and needs to be dealt with as soon as possible.

In the early stages of the disease, white fluffy mycelium appears on the substrate surface or casing layer, and its colour gradually darkens afterwards, with some forming mycelial clumps. Infected young mushrooms often appear deformed, swollen or with browned tissue, and in severe cases an entire cluster of mushrooms loses its commercial value. In mushroom houses with high temperature and high humidity and poor ventilation, the disease tends to be more severe.

The pathogen mainly enters the mushroom house with casing soil, compost, water sources, tools and the operations of workers, and can also spread via air currents. Older mushroom houses contain more residual pathogen spores, so if disinfection is not thorough, the disease is more likely to occur in the next crop.

Control should focus on prevention. The compost should be fully fermented, and the casing soil is best disinfected before use; during the fruiting period, pay attention to temperature and humidity control, strengthen ventilation, and avoid prolonged periods in a stuffy, damp environment. Once diseased mushrooms are found, they should be removed promptly and taken out of the mushroom house for disposal, and tools and hands that have touched the affected area should also be disinfected promptly.

After harvesting is finished, the mushroom house should be thoroughly cleaned and sterilised to reduce the source of pathogens for the next crop. For routine watering, stick to small amounts given frequently so that no water accumulates on the substrate surface, and combined with management measures such as ventilation and cooling, visible mycelial disease can be kept under control at the early stage of occurrence, ensuring the yield and quality of button mushrooms.