Control methods for physiological diseases of mushrooms

Mushrooms are quite sensitive to their environment. A poor cultivation environment will block their normal growth and development, produce various abnormal phenomena, and lead to reduced mushroom yields and lower quality. Common physiological diseases of mushrooms include excessive mycelial growth, hard cap opening, thin caps with early cap opening, and the appearance of soil-button mushrooms and hollow-stem white-core mushrooms. They are described below:
　　
Excessive mycelial growth
Symptoms: After the casing soil of the mushroom bed is watered, the fluffy mycelium of the mushroom keeps growing continuously toward the surface of the fine soil. In severe cases, it forms a fine, dense, water-impermeable mycelial mat, thereby delaying the time of fruiting and reducing mushroom yield.
Causes: This is mostly caused by watering the soil layer too lightly and too quickly, a mushroom house temperature above 22°C, humidity above 90%, and poor ventilation.
Preventive measures: 1. Try not to use spawn whose aerial mycelium grows too vigorously and too densely. 2. After casing, the soil layer should not be watered too hastily; watering should be done in the early morning and evening when the weather is cool, while increasing ventilation in the mushroom house and lowering the relative air humidity. 3. Immediately apply new casing soil, and spray a suitable amount of extra water to prompt the mycelium to form fruiting bodies in time. Alternatively, before small mushroom buds form, gently rake open the surface of the casing soil and increase ventilation to reduce relative humidity.
　　
Soil-button mushrooms (mud-topping mushrooms)
Symptoms: They mainly appear at the early stage of fruiting. The fruiting bodies are attached at a low position, usually occurring inside the compost, on the surface of the compost, or in the lower part of the coarse soil layer, and after growing larger they break through the soil and emerge pushing up mud.
Causes: 1. Soil mixed into the compost or uneven moisture in the casing layer; when the temperature, humidity and air conditions inside the compost are suitable for fruiting body growth, the mycelium knots around the soil and thickens to form primordia. After the primordia differentiate, they grow upward and emerge pushing up mud; if upward conditions are unsuitable, they may even turn around and grow downward under the bed, forming bed-bottom mushrooms. 2. Watering the coarse soil over too long a period, excessive ventilation of the mushroom house after watering, and a drop in mushroom house temperature all inhibit mycelial growth into the coarse soil and promote premature fruiting; covering with fine soil too late or too thickly, not watering in time, watering too quickly or too hastily, or ventilating too long after watering, insufficient moisture in the soil layer, and mycelium failing to climb onto the fine soil for a long time all lower the fruiting position. 3. Spraying fruiting water too early, too hastily, or in too large an amount inhibits upward growth of the mycelium in the soil layer and forces the mycelium to knot between the coarse soil particles, thereby lowering the fruiting position, causing sparse fruiting, abnormal fruiting positions, and an increase in soil-button mushrooms.
Preventive measures: 1. When spreading the compost, pick out all soil clumps mixed into it. 2. Apply casing soil evenly, and cover with fine soil as much as possible before small mushroom buds have formed in the coarse soil layer. 3. Water the soil layer evenly and ventilate appropriately; reduce ventilation after watering. 4. During the stage of mycelial cultivation in the soil layer, control the mushroom house temperature well, prevent it from being too low, and maintain a certain relative air humidity (about 85%) to promote mycelial growth into the soil layer, raise the mycelial growth position, and spray fruiting water properly and in due amount and time to prevent early fruiting and too low a fruiting position.
　　
Hollow-stem white-core mushrooms
Symptoms: The stem tissue of the mushroom is not solid, and a white, loose pith appears inside; after the mushroom body dries or is cooked, the pith shrinks or falls away, becoming hollow.
Causes: This is mainly due to improper water management. If the air humidity in the mushroom house is low and the soil layer has little moisture, especially if the water content of the coarse soil layer is insufficient, the rapidly growing fruiting bodies cannot obtain enough water from the soil layer, and the supply of nutrients is also reduced. In addition, the mushroom body itself continuously evaporates water, causing a water shortage in the middle of the stem and loose tissue, thus producing the hollow-stem white-core phenomenon.
Preventive measures: 1. When watering the coarse soil and spraying fruiting water and mushroom-emergence water, the amount of water should be sufficient to prevent the soil particles from becoming only superficially wet. 2. After fruiting begins, spray mushroom-emergence water once as much as possible to ensure that the coarse soil layer can be continuously replenished with water throughout the peak fruiting period. 3. During the mushroom-growing stage, frequently mist inside the mushroom house to increase humidity; the relative air humidity in the mushroom house should reach 90%. When the temperature is relatively high, ventilate in the early morning, evening, or at night to lower the temperature and prevent water from being lost too quickly.
　　
Hard cap opening
Symptoms: Before the mushroom fruiting body has matured, the cap and stem separate and split open, exposing pale red gills.
Causes: This is mainly due to sharp temperature changes (temperature below 18°C, with a temperature difference of about 10°C), which create a temperature contrast among the compost temperature, soil layer temperature and air temperature. The nutrient metabolism and physiological metabolism of the mushroom stem become disturbed, causing the stem rooted in the soil layer and the cap exposed above the soil surface to split because of unbalanced growth.
Preventive measures: Strengthen heat preservation measures in the mushroom house; do not ventilate at night, and do not let cold wind blow into the mushroom house. At the same time, regulate relative air humidity well to promote balanced growth of all parts of the mushroom body.
　　
Thin caps with early cap opening
Symptoms: The fruiting bodies have thin stems and thin caps, and open their caps early.
Causes: Too high a fruiting density, a relatively high mushroom house temperature, insufficient relative air humidity, a relatively dry soil layer on the bed surface, and rapid fruiting body growth can all lead to thin caps with early cap opening.
Preventive measures: Properly control the fruiting position; ventilation in the mushroom house should be done in the early morning and evening; lower the mushroom house temperature; and appropriately increase the moisture of the soil layer on the bed surface and the relative air humidity.