Identification, Occurrence and Control of Neurospora Disease in Edible Mushrooms

Neurospora can contaminate the spawn and substrate of all edible mushrooms. The most obvious symptom is the accumulation of a large number of conidia on the cotton plugs and the surface of the spawn, appearing as an orange-red powder layer that can reach a thickness of about 1 cm. Even slight air vibration will cause the conidia to spread with the airflow, resulting in the whole batch of spawn being ruined. It occurs most easily during the high-temperature, high-humidity plum rain season, and infection is even more likely when the cotton plugs become damp.

Poor-quality spawn: spawn that has been kept too long has weak mycelial vitality and is easily contaminated by Neurospora. Contaminated sealing material: sealing material (such as cotton plugs) that is damp, too loose or broken is one of the main causes of contamination by this fungus. In addition, improper operation, incomplete sterilization, poor sanitary conditions in the inoculation and culture environment, unclean inoculation tools, and lax aseptic technique by workers will greatly increase the probability of Neurospora infection.

Integrated control measures

It is necessary to create environmental conditions favorable to edible mushrooms and unfavorable to the occurrence of pests and diseases, and to isolate infection zones such as the raw material warehouse and mixing room from susceptible zones such as the spawn room, inoculation room, culture room and fruiting shed. The inoculation room and culture room should be cleaned regularly and thoroughly disinfected with a 1000-fold dilution of 20% azoxystrobin suspension concentrate or 10% difenoconazole water-dispersible granules combined with ultraviolet lamps, or with a high-efficiency environmental sterilizer. Before the substrate is brought into the room, the mushroom house and mushroom racks should be exposed to the sun for 2-3 days and disinfected with lime, formalin, etc. Contaminated spawn and diseased mushrooms should be taken out of the mushroom house and burned or buried deep. After each cultivation season ends, the mushroom yard should be thoroughly cleaned up.

Strictly control the spawn: choose varieties that are suitable for the local environment and have strong disease resistance. Use high-quality mother spawn and stock spawn that are young in age, strong in vitality and free of contamination, which helps to form a growth advantage as soon as possible after inoculation and resist Neurospora infection. Carefully select the planting spawn, eliminate abnormal strains, and prevent the spawn from carrying the fungus.

Strictly standardize cultivation operations: when mixing the substrate, choose fresh substrate free of insects and mold, and add 0.1% of the dry substrate mass of 50% carbendazim wettable powder, 0.1% quicklime, or a 0.2% potassium permanganate mixed solution when mixing, or mix the substrate with 0.1% of 70% thiophanate-methyl wettable powder. Appropriately increase the amount of lime (2%-4%), especially when cultivating with unsterilized substrate in the high-temperature season. Adjust the carbon-to-nitrogen ratio and pH value of the substrate well. Adjust the water content of the substrate well, using the standard that when the substrate is squeezed in the hand, water just does not come out between the fingers. When filling bags, the tightness should be appropriate.

In addition, the substrate should be used as soon as it is mixed to prevent souring. During sterilization, first exhaust all cold air and ensure sufficient sterilization pressure and time; the spawn bags in the cooker should not be placed too tightly, so as to avoid poor steam circulation. Strict aseptic technique should be implemented in links such as inoculation and mycelial incubation. Avoid damp sealing material and be careful to prevent spawn bags from being damaged. Choose the best sowing period during inoculation and appropriately increase the sowing amount, so as to facilitate rapid mycelial growth and form a mycelial growth advantage. During mycelial incubation and fruiting, control the temperature and humidity in the shed well, pay attention to ventilation and light regulation, and ensure good environmental conditions.

Chemical control: the principle of minimum use should be followed when using chemical pesticides. If Neurospora contamination is found, first carefully remove the contaminated spawn bags to the outdoors for deep burial or burning, and avoid the dispersal of Neurospora spores during the removal process. At the same time, thoroughly disinfect the mushroom house with thiophanate-methyl and azoxystrobin.