Control Methods for the Large Button Mushroom and Xylaria (Cracked Cap Fungus)

The large button mushroom and Xylaria (chicken-foot fungus) are both major diseases of edible mushrooms. Both are parasitic diseases that live on the mycelium of edible mushrooms and absorb nutrients from it. Once the disease occurs on the mushroom logs or beds, the infected parts of the logs or beds will no longer produce mushrooms. The control methods are described below:

1. Large button mushroom

This pathogen mainly infects oyster mushrooms, shiitake mushrooms, enoki mushrooms, etc.

1. Symptoms. The disease first appears on the mushroom logs or beds as small white round granules with a hard texture, shaped like buttons. They later gradually merge into patches and turn brown, with an uneven surface and varying sizes. On affected logs, the substrate becomes loose, gives off an unpleasant odor, and the mycelium of the edible mushroom recedes; already formed primordia and young mushrooms turn yellow and rot.

2. Disease conditions. The mycelium of the large button mushroom grows at temperatures of 15°C to 40°C, with an optimum relative air humidity of 80% and a substrate pH of 5.5 to 5.8. Temperature is the key factor in disease occurrence. When the temperature is 30°C to 40°C, the mycelium on the logs grows poorly and the large button mushroom is likely to occur. Conversely, if the mushroom house temperature is below 25°C and the edible mushroom mycelium grows vigorously, the logs are of good quality and have strong stress resistance, the large button mushroom occurs little or not at all.

3. Control measures. (1) Select high-quality spawn with strong stress resistance and of the appropriate age. Prepare the substrate scientifically so that it is rich and balanced in nutrients. The moisture content and pH of the substrate must be suitable, and sterilization must be thorough to ensure quality. (2) Regulate the mushroom house temperature well. During the mycelium-running stage, keep the mushroom house temperature at 20°C to 25°C, and during fruiting keep the temperature below 15°C. (3) Logs already infected by the large button mushroom must be burned immediately. When growing with a casing soil, dig out the substrate and casing soil and burn them, and spread lime or spray Kemeiling on the affected area. (4) During mycelium running or in the early stage of the disease, spray a 1000-fold dilution of Kemeiling at 200 milliliters per square meter. (5) Change the cultivation site. When conditions permit, once infection by the large button mushroom occurs, a new mushroom house can be built elsewhere, which can effectively cut off the transmission route of the pathogen and prevent further spread. If an old mushroom house is used for cultivation, it should be thoroughly fumigated and disinfected after harvesting is completed.

2. Xylaria (chicken-foot fungus)

This pathogen mainly harms shaggy ink cap mushrooms (Coprinus comatus), and secondly infects button mushrooms (Agaricus bisporus).

1. Symptoms. Xylaria rarely infects during the mycelium-running stage of Coprinus comatus, but after casing soil is applied to Coprinus comatus and its mycelium spreads into the casing layer, if Xylaria is present, the two kinds of mycelium quickly twist together, and Xylaria then parasitizes the Coprinus comatus mycelium and then grows and spreads rapidly. Affected logs or beds stop producing mushrooms, the substrate becomes loose, and already formed mushroom buds die. Xylaria fruiting bodies appear on the beds. The fruiting bodies are light brown at first, later brown to black, and often have 2 to 5 stalks joined together, with pointed, slender tips, brown in color, shaped like chicken feet.

2. Disease conditions. The mycelium of Xylaria grows best at 25°C to 30°C; above 32°C or below 20°C it grows very slowly, and below 15°C it hardly grows at all. The optimum relative air humidity for growth is 85% to 95%. Poor ventilation, high moisture content in the substrate and casing soil, and a thick casing layer all favor the occurrence of Xylaria.

3. Control measures. (1) Xylaria is mainly spread by contaminated casing soil, so the casing material must be disinfected. The method is to first sun-dry the casing soil for 3 to 5 days, then spray it with a 5% formaldehyde solution, pile it up, cover it tightly with plastic film, fumigate for 24 to 36 hours, then spread it out to let the chemical smell dissipate before use. (2) Disinfection must be done well before bringing materials into the mushroom house; the bed frames and all facilities used in the mushroom house must be cleaned and disinfected. (3) Strictly control the temperature, humidity and ventilation of the mushroom house. Keep the mushroom house temperature below 20°C, the substrate moisture content at 60% to 65%, and the casing soil moisture content at 18%, with a casing thickness of 3 cm. When the humidity in the mushroom shed is 80% to 90%, pay attention to ventilation. Strictly prevent excessive moisture content in the substrate and casing soil and excessively high relative air humidity. (4) Carry out mycelium running and fruiting in separate locations in stages. Mycelium running can be done indoors or in a greenhouse, with the temperature kept at 20°C to 30°C. Casing and fruiting should be done after the autumn weather turns cool, keeping the mushroom shed temperature at 10°C to 15°C, avoiding high temperatures, which can effectively control the occurrence of Xylaria. (5) Fruit without removing the bag, with casing soil applied. That is, after the well-colonized mushroom bags are opened at the top, place them directly on the bed, and cover only the substrate surface at the bag opening with a 3 cm thick layer of casing soil; this can control the spread of Xylaria. (6) When Xylaria is found on the beds, stop watering immediately, dig out the diseased fungus along with the surrounding substrate and casing soil, and bury it deeply or burn it far away from the mushroom shed. Spray the infected area with 5% to 10% lime milk, cover with fresh soil, and cover well with plastic film. (7) Rotation of mushrooms and vegetables is encouraged, as it helps change the ecological environment and inhibit the occurrence of the pathogen. Changing the site and building a new mushroom house can cut off the transmission route of the pathogen and is an effective method for controlling Xylaria.