What are the control methods for mushroom rust spot disease?

Mushroom rust spot disease, also called brown spot disease or bacterial blotch, is caused by Pseudomonas tolaasii, an acidophilic species of the genus Pseudomonas. It spreads through insects, tools, the hands of workers and other carriers. The disease is severe when the casing soil of the mushroom bed has a pH below 5.5, when ventilation is poor, when humidity is too high, and when the mushroom caps remain constantly moist and sticky after watering. Its symptoms are: it generally infects only the epidermal layer of the mushroom cap, causing spots of varying size that are initially yellowish-brown and rust-like in appearance, which later gradually turn brown or black, and sometimes scars with mucus also appear on the caps. The disease spreads rapidly; when the infection is mild the mushroom shape is normal, but in severe cases as many as several hundred sunken spots appear on the cap, or the lesions enlarge and become stripe-like, and the fruiting bodies become deformed. The stipe is sometimes also infected and develops longitudinal sunken spots.

Control methods:

(1) When casing, adjust the pH of the soil layer to 6.5-8, and strengthen ventilation during cultivation.

(2) When the disease is severe, control the temperature and humidity of the mushroom house. Spray the mushroom bed once every other day with 0.04% oxytetracycline and 0.04% streptomycin respectively. Subsequent watering of the mushroom bed should adjust the pH to 8, until the pH of the soil layer remains at 6.5-7.5.

(3) Sprinkling a thin layer of quicklime powder on the surface of the casing soil layer can also effectively control the development of the disease.