Diseases and Pests of the Fragrant Mushroom (Brown Mushroom) and Their Control Methods

The fragrant mushroom, also known as the “brown mushroom,” is renowned both at home and abroad for its rich aroma, delicious taste, thick flesh, abundant nutrition and unique flavor, and has long enjoyed the reputation of “Pearl of the Grassland, King of Mushrooms.” However, its growing and living conditions are relatively enclosed, dark and humid, which very easily leads to the occurrence of diseases, pests and mites, destroying its original value. So what kinds of diseases and pests affect the fragrant mushroom (brown mushroom)? And how should we control them?

1. Ink cap. In fragrant mushroom cultivation, the commonly occurring ink cap diseases include the crystal ink cap, the shaggy ink cap, the black-ink ink cap and the dung ink cap. Ink cap damage appears 7—15 days after sowing the fragrant mushroom. Because the ink cap grows noticeably faster than the fragrant mushroom, it seizes the water and nutrients in the compost, causing a reduction in fragrant mushroom yield. Before the ink cap fruiting bodies appear, their mycelium is very difficult to distinguish from fragrant mushroom mycelium. To avoid the occurrence of ink cap, during fermentation one must prevent the culture material from being stale and incompletely fermented, and prevent excessively high nitrogen content in the culture substrate. Therefore, the compost material must be fresh and not moldy, so as to avoid introducing contaminating microbes; the carbon-to-nitrogen ratio of the compost must be reasonable, and the water content of the material must be appropriate. Once ink cap appears on the mushroom bed, it must be pulled out promptly before the caps open, so as to prevent the basidiospores from dispersing and spreading.

2. Green mold. Green mold is one of the main threats in fragrant mushroom production. It occurs 2-7 days after inoculation, mainly showing up after sowing wheat-grain spawn: the mycelium does not germinate, the wheat grains turn green, and it may even spread through the entire sowing layer. The cause is high air humidity together with high temperature in the production site.

Its control method is: strengthen ventilation, lower the temperature and reduce humidity. In severe cases, the green portion of the inoculated layer must be turned over and removed, and sowing must be redone, also called reseeding.

3. Dead mushrooms. In the mushroom house, mushroom buds wilt, turn yellow and finally die, sometimes dying in whole batches. The causes are: when the fruiting bodies are only the size of a sesame seed or soybean, if the mushroom house encounters a high temperature above 23°C for a prolonged period, the fruiting bodies will die in batches; when cold air arrives, heavy watering of the mushroom bed increases the temperature difference between the compost and the casing soil layer, reducing the metabolic capacity of the fruiting bodies and causing them to die; and careless damage to surrounding small mushrooms during picking causes localized dead mushrooms.

Control methods:

① According to the climate characteristics, reasonably arrange the sowing season, avoid fruiting during high temperatures; when sudden high temperatures occur during fruiting, stop watering the bed surface and ventilate heavily at night.

② After cold air arrives, never water heavily.

③ When picking mushrooms, hold the cap with your hand, twist it once and then pull it up, so as to avoid disturbing the surrounding casing soil.

4. Thin skin and early opening of the cap. Thin skin and early opening of the cap means the fruiting body has a thin stalk and a thin cap that opens early; such mushrooms are of poor quality. Causes: raw compost, a thin compost layer, excessive dryness, too thin a casing layer, insufficient water content; high fruiting density, high temperature, fast growth of fruiting bodies, early maturity and a dry bed surface.

Control methods:

① The compost should be moderately decomposed, the material layer should not be too thin, and a certain humidity should be maintained; the casing soil should not be too thin or too dry.

② Prevent excessively dense fruiting, and do not spray water on the first flush.

③ During the peak fruiting period, the mushroom house should be ventilated in the morning and evening or at night to lower the temperature inside, appropriately increase the moisture on the casing soil surface, and raise the air humidity in the mushroom house.

5. Water rust spots. Rust-colored spots appear on the mushroom caps. Causes: after the fragrant mushroom fruiting bodies emerge from the soil, if the bed surface is sprayed with water and not ventilated in time, the air humidity in the mushroom house is too high and water often accumulates on the surface of the mushroom bodies; during the fruiting period, if the air is humid and stuffy and the mushroom house temperature is above 18°C, it is even more likely to occur.

Control method: after spraying water during the fruiting period, pay attention to ventilating the mushroom house; only close the doors and windows after the water droplets on the surface of the mushroom bodies have evaporated.

6. Maggot damage. This insect is a major pest of the fragrant mushroom, oyster mushroom and others. The larvae damage the mycelium and fruiting bodies; infested mushroom buds turn yellow, shrivel and die. After the fruiting bodies emerge from the soil, the larvae gather on the mushroom base or spread over the entire mushroom body, making it pale red. This insect affects not only yield but also quality.

Control methods:

① Do a good job of environmental sanitation, and promptly burn or deeply bury discarded mushrooms and spoiled fruiting bodies.

② Install window screening on the doors, windows and ventilation holes of the mushroom house to block the entry of pests.

③ Chemical control. Hang cotton balls or cloth strips dipped in undiluted dichlorvos at the ventilation openings and on the mushroom bed to drive away adult insects.

④ Light trapping. Place an iron basin containing an aqueous dichlorvos solution under an electric light to attract and kill adult insects.

7. Mite damage. Mites belong to the phylum Arthropoda, class Arachnida. From the larval stage onward they can feed on fragrant mushroom mycelium, and they are the most harmful, reducing the finished-product rate of spawn and causing yields and quality to drop substantially. Damage characteristics: they feed on mycelium, and in severe cases can eat all the mycelium and young fruiting bodies.

Control methods:

① Do a good job of environmental sanitation; the spawn culture room and the edible mushroom cultivation site must be clean and hygienic, and contaminating microbes must be eliminated.

② Promptly dispose of waste spawn bottles, and promptly compost or deeply bury waste material to eliminate breeding grounds for mites.

③ Sugar-water trapping: mix dichlorvos into sugar water and soil, place it on plastic film near the mushroom bed to attract mites to come and feed on the sugar, thereby killing them.

In short, in dealing with fragrant mushroom diseases and pests, one must achieve “prevention first, integrated control,” and strangle diseases and pests in the “cradle” so as to achieve high, stable yields and pollution-free produce!