Identification and Control Methods for Common Diseases of Edible Fungi

Brown rot, also known as white rot, wet bubble disease, etc. When diseased mushrooms are infected at a young stage, they cannot further differentiate and develop, and later form deformed mushrooms, often with a layer of "white fuzz" growing on the surface, which is the mycelium of the pathogen. When the temperature is above 20°C, over 4 to 5 days, the diseased mushrooms darken in color, then rot, exuding a brown (soy-sauce-like) liquid and becoming decayed and foul-smelling; below 20°C, this process takes longer. When the fruiting body is infected at the mid stage, brown lesions appear on the cap, the stipe becomes swollen and thick, and then the mushroom body softens. Cutting open the diseased mushroom reveals that its interior changes from white to grayish-white, and after the mushroom body soft-rots it becomes grayish-brown. The pathogen of this disease is Mycogone perniciosa.

Brown spot disease, also known as dry bubble disease, black spot disease, etc. When disease occurs early, it causes irregular development of primordia and deformed growth; when young mushrooms are infected, brown streaks appear on the stipe, brown spots are scattered on the cap, and the diseased mushrooms grow to one side. Cutting open a diseased mushroom for observation, its internal tissue is yellowish-brown, dry and loose, but the mushroom body does not rot and has no foul odor. The pathogen of this disease is Verticillium.

Soft rot, also known as downy mildew, wet rot, etc. After the mushroom bed is covered by the grayish-white mycelium of the pathogen, it turns dark grayish-green or dark brown. The edible fungus mycelium loses vitality due to lack of oxygen and poisoning by the pathogen's secretions, and afterward it is very difficult for mushrooms to emerge; diseased mushrooms develop from the base and extend upward to the cap. In the early stage, pale brown water-soaked lesions of varying sizes appear on the cap, which are then covered by the pathogen and subsequently rot, collapsing at a touch. The pathogen of this disease is Cladobotryum dendroides.

Rust spot disease, also known as spot disease. The pathogen forms rust-colored (dark yellow-red) lesions on the cap, with neat edges and a sunken center. After the spots dry and shrink, the cap cracks. The stipe and gills are less affected. When water droplets collect on the cap surface and do not evaporate for a long time, the incidence rate at that spot is high. This disease is a bacterial disease, and the pathogen is Pseudomonas tolaasii.

Yellow spot disease: in the early stage of infection, small spot-like light yellow diseased areas appear on the cap, expanding as the mushroom grows and infecting other fruiting bodies, then the color deepens and spreads to the entire cap. In the late stage of infection, the mushroom body secretes yellowish-brown water droplets, the diseased plants stop growing, then shrink and die. This disease is a bacterial disease, and the pathogen is Pseudomonas.

Under conditions of sustained high temperature, high humidity, and poor ventilation, combined with poor selection of spawn, improper production techniques, and dirty, messy environments, the above diseases have a relatively high incidence rate. Therefore, prevention and control should follow the principle of "prevention first, integrated control": 1. Promote cooked-substrate cultivation. When fermenting and mixing the substrate, add appropriate amounts of Amusi warming fermentation agent, Jingmeiling, Bijieshi, and Lixin Junwang, etc., to enhance their own disease resistance. 2. Strictly follow the processes of fermentation, sterilization, inoculation, and culturing, etc., and avoid high temperatures during the mycelium growth period. The casing soil material should be treated with formaldehyde. Old mushroom sheds should be fumigated with sulfur. 3. After harvesting the first flush of mushrooms, stop watering for 2 days, then spray once with Bordeaux mixture, etc. Spray 2 times consecutively, and spray once more after primordia appear. For casing cultivation, after the first flush of mushrooms, use Bordeaux mixture for flood irrigation. 4. In the early stage of disease, promptly remove diseased mushrooms, scrape off the substrate surface, and spray a 100-fold mushroom disease-removal king solution, Bordeaux mixture, bleaching powder solution with 150 mg/L available chlorine, 100 to 200 international units of agricultural streptomycin, etc. For bed cultivation, remove the diseased substrate and scatter lime powder and bleaching powder to eliminate sources of infection and avoid human transmission.