Control Methods for Fungal Diseases of Edible Fungi

I. Brown Rot Disease

Also known as white rot, wet bubble disease, and Mycogone disease. It mainly affects the button mushroom (Agaricus bisporus), straw mushroom (Volvariella volvacea), and oyster mushroom (Pleurotus ostreatus).

1. Symptoms

It infects only the fruiting bodies, not the mycelium. When the fruiting body is infected, a layer of white cottony pathogenic mycelium appears on the surface, the stipe swells into a blister-like deformity, and then it rots and dies, hence the name wet bubble disease. If the fruiting body is infected before differentiation, differentiation is blocked and an irregular tissue mass forms, with white fuzzy mycelium on the surface; the tissue mass gradually turns brown, oozes brownish fluid from within and rots, giving off a foul odor.

2. Causes

The pathogen is Mycogone perniciosa. The chlamydospores of Mycogone can remain dormant in the soil for several years, and the primary infection mainly comes from the soil; secondary infection and disease spread within the mushroom shed are mainly through the pathogen spores transmitted via humans, pests, tools, or watering. The disease is severe when the fruiting room is hot and humid with poor ventilation, and it rarely occurs below 10°C.

3. Control Measures

(1) Screen doors and screen windows should be installed in the fruiting room, and the fruiting room, bed frames, and tools should be strictly disinfected to thoroughly kill pathogens and pests.

(2) The casing soil must be disinfected. Pasteurize the casing soil: hold at 60-70°C for 1 h.

(3) The compost must undergo post-fermentation treatment or pasteurization.

(4) The cultivation season should be chosen well, with the fruiting period of the first flush avoiding the high-temperature season above 25°C.

(5) If the disease occurs during cultivation, stop watering and strengthen ventilation to lower the temperature and humidity; if the disease is severe, promptly destroy the diseased mushrooms and clean the bed surface. Alternatively, cover during the day and open at night to lower the shed temperature as much as possible, thereby suppressing the damage from the pathogen.

II. Brown Spot Disease

Also known as dry bubble disease, black spot disease, and Verticillium disease. It mainly affects the button mushroom and oyster mushroom.

1. Symptoms

Brown spot disease spreads very quickly and has a strong infective ability against fruiting bodies. After the mushroom buds are infected, they form relatively dry grayish-white tissue masses that cannot differentiate to form stipes and caps. After the fruiting body is infected, the pathogenic mycelium can invade the pith of the fruiting body, causing the stipe to swell abnormally and turn brown, the cap to develop slowly, and the fruiting body to become deformed and rigid. Many irregular brown spots the size of pinheads also appear on the cap, and the spots gradually enlarge and become sunken; the sunken parts are gray and filled with conidia of Verticillium, but the mushroom body does not rot and has no foul odor, and finally it dries, cracks, and dies.

2. Causes

The pathogens are Verticillium fungicola, Verticillium psalliotae, and Verticillium agaricinum. Verticillium mainly survives in soil and air, with an optimum growth temperature of around 22°C, and its vitality is very weak below 12°C. Its conidia can adhere to soil, tools, humans, and insects, so the primary infection may be caused by the germination of pathogen spores surviving in soil and air, while the rapid spread after the disease occurs is transmitted through humans, tools, insects, and even watering. The disease is prone to occur when the fruiting room has poor ventilation and high air humidity.

3. Control Measures

Refer to the control of brown rot disease.

III. Soft Rot Disease

Also known as cobweb disease, wet rot, and Cladobotryum disease. It mainly affects the button mushroom, oyster mushroom, and golden needle mushroom (Flammulina velutipes).

IV. Gill Mold Disease

Also called cap spot disease or Cephalosporium disease, it is a type of disease that mainly occurs on the gills. It mainly affects the button mushroom, shiitake mushroom (Lentinula edodes), and oyster mushroom.

V. Damping-off Disease

Also called wilt disease, it mainly affects the button mushroom and oyster mushroom. Control measures: refer to the control of brown rot disease.