Control of soft rot of Pleurotus ostreatus

The disease is caused by Dactyliumdendroides infection in the subphylum Pleurotus ostreatus, also known as dendritic whorl mold, cobweb mold, etc., which is a harm to the soft rot of Pleurotus ostreatus fruiting body.

The main results are as follows: (1) pathogenic characteristics and harmful symptoms: pathogenic hyphae are white, aerial hyphae grow exuberantly and densely, cotton-like; conidiophores grow directly from aerial hyphae, slender and sparse; conidium peduncles are whorled, apical tip slender, solitary or clustered with 3 conidia; conidia are colorless or yellowish, long ovate or pear-shaped, with a size of 20 μ m ~ 5 μ m.

At the initial stage of the disease of the bacterial bed, a thick layer of white woolly hyphae grew on the material surface or overlying soil layer. when the temperature and humidity were suitable, the bacterial bed was often covered to form a cotton quilt, which was easily mistaken for Pleurotus ostreatus hyphae. When the fungus bed is infected seriously, the primordium of the affected part can not be formed or inhibited, and further damage the growing fruiting body; when the fruiting body occurs, it starts from the base of the fungal stalk, gradually spreads upward, and shows the symptom of light brown soft rot. After serious damage, the stalks and pleats were covered with white pathogenic hyphae, or the infected mushrooms together with their fungal beds were surrounded by the pathogenic hyphae in the shape of a cobweb, resulting in the appearance of light brown soft rot in the whole of the diseased mushrooms; the pathogenic hyphae became light red in the later stage, and purplish red pigments were produced in the center of the disease. After Pleurotus ostreatus is infected with this disease, the fruiting body is generally not deformed and does not emit bad smell, but the diseased mushroom falls immediately with hand touch; the diseased mushroom with mild disease and no symptoms of soft rot has hindered its growth and development, its appearance is yellowish white and lifeless, which is obviously different from the normal healthy mushroom.

(2) infection pathway and occurrence conditions: the pathogen is a kind of weakly parasitic soil fungus, which likes acidic, moist and organic environment, and there are the most fertile seedbeds, vegetable garden soil and topsoil. The pathogen can invade the bacterial bed directly with the culture material or soil, and the conidia can spread with the action of airflow, insect, diseased mushroom and water splash.

The germination rate of pathogenic conidia was the highest at 20 ℃, was disadvantageous to germination at 25-30 ℃, and was easy to die at high temperature (60-70 ℃). The optimum temperature for mycelium growth was 25 ℃, and the optimum pH was 3.4 (growth range 2.2-8.0). Conidia germination and mycelium growth are most suitable for saturated humidity. The disease is easy to occur when the Pleurotus ostreatus bed is in direct contact with the bacteria-carrying soil, or when using open-field sunny beds, outdoor plastic greenhouses and solar greenhouses as mushroom farms, or when cultivated in civil air defense fortifications with medium temperature and high humidity.

(3) Control measures

1) refer to the comprehensive management measures of diseases and insect pests in the cultivation of Pleurotus ostreatus.

2) the ground and soil in direct contact with the bacterial bed must be disinfected and pretreated when in use.

3) in the mushroom growing stage, the dry and wet alternating moisture management should be adopted, and a good ventilation environment should be maintained. During the turning tide, in addition to cleaning the bed surface, 1%-2% lime clear liquid should be sprayed regularly to prevent the bacterial bed from being acidified too heavy.

4) once the disease occurs, water spraying should be suspended, ventilation and dampness should be stopped immediately, diseased mushrooms should be removed, pathogenic bacteria should be removed, and the covered soil contaminated in the afterlife should be cleared or replaced. After reducing dampness, the affected area can be sprayed with 2% formaldehyde solution, or 50% carbendazim 800-1200 times solution, or 5% lime solution, or 150~250mg/kg bleach solution, or covered with thin lime powder or bleach powder in the affected area.