What are the control methods for bacterial blotch disease in oyster mushrooms?

Rust-colored or dark brown spots appearing on the caps and stipes of oyster mushrooms are called bacterial blotch disease of oyster mushrooms. This disease is a bacterial disease that easily occurs during the fruiting body growth stage of oyster mushrooms. The pathogen causing this disease is a Pseudomonas bacterium that is extremely widely distributed in nature. In the early stage of the disease, the spots are only the size of a needle tip and light in color, generally not affecting commercial value. As the disease worsens, the spots rapidly enlarge and their color continuously deepens, often appearing oval or spindle-shaped, or connecting with each other to form irregular large patches, with rust-yellow discolored areas around the patches. When the mushroom bed is severely infected with this disease, the fruiting bodies turn entirely scorched yellow, causing light-colored mushrooms to become yellow mushrooms and dark-colored mushrooms to turn sauce-colored. When bacterial blotch disease is mildly harmful, although it affects the growth and development of the fruiting bodies, it does not pose a threat. After the damage worsens, it will not only cause the death of the fruiting bodies but also affect the normal growth of the next flush of mushrooms, and can cause cross-infection with other diseases and pests. Fruiting bodies damaged by bacterial blotch disease become shriveled and contracted, with poor color and low commercial value. Severely affected diseased mushrooms have distorted gills, with spore powder that has not been fully released often trapped within the gills, and the caps also become wrinkled and cracked due to the gradual sinking of the spots, losing commercial value.

Preventive measures: If bacterial blotch disease occurs, ventilation should be strengthened and relative humidity reduced. For chemical control, 5% lime clear liquid, 1:600 diluted bleaching powder solution, 500-800 times diluted Ansol fungicide aqueous solution, oxytetracycline, streptomycin, gentamicin or chloramphenicol solution at 120 units per milliliter, or a mixture of 3 parts bleaching powder and 1 part soda ash made into a 0.5% mixed solution can be used for spraying. If the oyster mushrooms have already died from the damage, or the mushroom bed is severely infected, then all fruiting bodies on the mushroom bed should be promptly removed, the yellowed, aged and infected surface mycelium scraped off, the bed surface cleaned thoroughly, and after slight air-drying, a thin layer of lime powder or a small amount of bleaching powder should be sprinkled onto the mushroom bed to reduce the pathogen population on the bed and prevent the recurrence of bacterial blotch disease after the next flush.