Control of bacterial Brown spot of Edible Fungi

I. pathogens and occurrence conditions

The bacteria causing bacterial brown spot of edible fungi is Pseudomonas Tora, which is widely distributed in nature. The pathogen can easily multiply under the conditions of high temperature, high humidity, poor ventilation and so on. Reproduction is accelerated when the temperature is above 18 ℃ or the air relative humidity is above 85%. During the period of mushroom emergence, the water with bacteria was sprayed on the fruiting body, the ventilation of the mushroom bed was poor, the humidity was too high, the surface of the mushroom cover and culture medium were stagnant for a long time, and the same mushroom and the same variety were planted repeatedly in the greenhouse for several years. the disease can be caused by the accumulation of condensed water on the bag or bacteria in the greenhouse film. The disease can also float in the air and is transmitted by mushroom flies, nematodes and workers.

Second, main symptoms

1. Matrix pollution. The surface of the Agar medium contaminated by bacteria formed colonies visible to the naked eye, which were wrinkled and irregular protruding from the surface to the inside, and then rotted and mildewed. When the bag material medium was contaminated by bacteria, the initial water content increased and there was sour smell, while the later culture material rotted and the sour smell became more serious.

two。 Mushroom body pollution. The mushroom body infected by pathogen forms irregular brown spots on the surface of the mushroom cover, which is round or diamond-shaped, the size is more consistent, the edge is neat, the middle is slightly sunken, there is a thin layer of bacterial pus on the surface, gently scraping the disease spot with fingernails, it can be seen that the flesh below is still white. In the case of severe infection, there are dozens to hundreds of spots on the single cap of the fruiting body, the fruiting body is dry and wrinkled, stops growing, and decays when there is too much water.

III. Comprehensive prevention and control

1. To ensure the hygiene of the mushroom room. The cultivation ground is far away from the chicken, duck and poultry house, and it is strictly forbidden to throw fertilizer and contaminated bacterial sticks around to ensure a clean environment. The facilities in the mushroom room should be disinfected regularly, the bed frame and supporting materials should be removed and dried in the sun, and the floor of the mushroom room should be disinfected with bleach of 150mg/L concentration. Before entering the shed, the bacteria bag was fumigated with 10~15g/ cubic meters of sulfur and steamed in the mushroom shed for 2-3 days, and the relative humidity was kept below 85%. During the period of mushroom production, the relative humidity in the mushroom room should not be too large, and ventilation should be strengthened to keep the air fresh. in addition, the greenhouse had better be covered with drip-free plastic greenhouse film.

two。 Select high-quality culture materials. Choose the culture material without diseases and insect pests and no mildew, the wheat bran in the culture material formula in the high temperature season should not be higher than 10%, it is best not to add corn flour, and add the right amount of lime. The water content of the culture material is not more than 65%, the air relative humidity of the mushroom room during the strain culture period is not higher than 70%, and the soil covering material should be disinfected with formaldehyde.

3. Choose a good breed. Select excellent varieties with strong impurity resistance, grasp the cultivation season, inoculate bacteria in time, so that spring planting should not be too late and autumn planting should not be too early.

4. Strengthen the water management in the mushroom stage. The mushroom room should be dry during the mushroom production period, and the ventilation should be strengthened when ensuring the appropriate humidity. Do not spray columnar water on the small mushroom buds during the mushroom bud stage. It is better to spray the water sterilized with bleach stored one day ago (the concentration is 150mg/L). Avoid stagnant water on the medium or fruiting body.

5. Treatment of diseased mushrooms. Once the mushroom body is infected with bacteria, it should be removed in time, including the infected young mushroom buds. When removing diseased mushrooms, the mushroom roots should be removed, and the surface of the culture medium should be cleaned to ensure that the nutrients in the substrate are not consumed.

6. Chemical control. When the condition of ① is mild, 2000 times of agricultural streptomycin can be sprayed on the lesion. ② sprayed diseased mushroom body with 150mg/kg available chlorine to reduce the incidence. ③ sprayed the material surface or fruiting body with 3000-fold "mushroom guard" liquid, once every 7-10 days, and mixed the material with 3000-fold liquid "mushroom guard" to prevent bacteria infection during the whole growing period. ④ sprayed the mushroom body with 2000 times of "mushroom disease nemesis" liquid.