Symptoms and control of mushroom brown spot

Mushroom brown spot, also known as dry bubble disease, the distribution is more common, often occurs in the mushroom bed, the harm is very great.

Symptoms: when the disease occurs, brown spots and depressions are formed on stalks, umbrellas and pleats. Mushrooms often lose their toughness and show deformities. Mushrooms rot in severe cases. The young mushroom is deformed, the edge of the umbrella is serrated, or the stalk is curved, some are shaped like garlic, and the stalk is thicker than the cap. When the disease occurs on the mushroom, it often produces local brown spots, and the diseased mushroom becomes dry and leathery in the later stage, and produces a gray mildew layer in the diseased part. Unlike white rot, diseased mushrooms rot more slowly, without brown mucus or stench. In the early stage, the symptoms of white rot are similar to those of brown spot.

Infection: the primary infection source of circulating bacteria usually comes from the covered soil, and the bacteria-carrying soil is the main source of the disease. Subsequently, it is mainly due to the spread of bacterial spores on infected mushrooms with airflow; manual activities, such as hands, tools, etc., can spread when they come into contact with diseased mushrooms. The disease is mostly from the residue after mushroom harvesting, mainly from the broken stalk, the first infection, and then spread.

Disease conditions: the degree of disease occurrence is closely related to temperature and humidity, mushroom bed temperature is too high, poor ventilation, humidity, and bacteria-carrying waste stacked on the mushroom bed and other factors will lead to the occurrence of the disease.

Prevention and control methods:

1. Get rid of diseased mushrooms in time. When diseased mushrooms are found, the diseased mushrooms, together with mycelium and culture materials at a depth of 10 cm, should be dug up and burned or buried deeply, and the diseased holes should be filled with disinfectant soil. At the same time, use formalin disinfection tools to prevent bacterial transmission.

2. Reduce the temperature and humidity. Under the condition of not cooling the mushroom room, open the window to ventilate and reduce the temperature and humidity. Control the air humidity so that the relative humidity does not exceed 95% and lower the temperature to less than 17 ℃.

3. Chemical control. In order to prevent the occurrence of diseases, the infection rate can be greatly reduced by spraying 1 ∶ 1 ∶ 300 Bordeaux solution to cover the soil surface before mushrooms grow. You can also spray the surface of the mushroom bed with 100 grams of carbendazim or 200 grams of thiophanate methyl plus water of 100 tons per 100 square meters.

4. Others. If the disease continues to develop after adopting the above measures, all the covered soil can be removed, replaced with disease-free soil, re-covered, and the pathogenic factors can be controlled.