Control Methods and Technical Key Points for Physiological Diseases of Button Mushrooms

Button mushrooms are relatively sensitive to their environment. A poor cultivation environment will hinder their normal growth and development, produce various abnormal phenomena, and lead to reduced yield and lower quality. Common physiological diseases of button mushrooms include excessive mycelial growth, hard opening of the caps, thin-skinned early opening, and the appearance of soil-level mushrooms and hollow-stemmed white-core mushrooms. They are described below:

Excessive mycelial growth

Symptoms: After the mushroom bed is cased and watered, the fluffy mycelium of the button mushroom will continuously grow toward the surface of the fine soil. In severe cases, it will form a fine, water-impermeable mycelial mat, thereby delaying the time of fruiting and reducing the yield of button mushrooms.

Causes: This is mostly caused by the soil layer being watered too lightly and too quickly, the mushroom house temperature exceeding 22 degrees Celsius, the humidity exceeding 90%, and poor ventilation.

Preventive measures: 1. Try not to use spawn with excessively vigorous and dense aerial mycelial growth. 2. After casing, the soil layer should not be watered too hastily. Spraying should be carried out in the cool weather of early morning and evening, while increasing ventilation in the mushroom house and reducing the relative air humidity. 3. Immediately re-case the soil and spray a somewhat larger amount of water to encourage the mycelium to form fruiting bodies in time. It is also possible to gently rake open the casing surface before small mushroom buds form, increase ventilation, and reduce relative humidity.

Soil-level mushrooms (mud-topping mushrooms)

Symptoms: They mainly appear in the early stage of fruiting. The fruiting bodies are located low, usually occurring within the compost, on the compost surface, or in the lower part of the coarse soil layer. After growing, they break through the soil and emerge with mud on top.

Causes: 1. Soil mixed into the compost or uneven dryness and moisture in the casing layer, when the temperature, humidity, and air conditions within the compost are suitable for fruiting body growth, will cause the mycelium to twist and thicken around the soil to form primordia. After the primordia differentiate, they grow upward and emerge with mud on top. If the upward conditions are unsuitable, they will even turn around and grow downward beneath the bed to form bottom-bed mushrooms. 2. If the coarse soil is watered over too long a period, or after watering the mushroom house is ventilated too much and the temperature drops, mycelial growth into the coarse soil will be inhibited, promoting premature fruiting. If the fine soil is applied too late or too thick, watering is not timely, watering is too fast or too hasty, or ventilation after watering lasts too long, the soil layer humidity will be insufficient and the mycelium will be slow to climb onto the fine soil, all of which will lower the fruiting position. 3. If water is sprayed too early, too hastily, or in too large an amount at the fruiting stage, upward growth of the mycelium in the soil layer will be inhibited, forcing the mycelium to twist among the coarse soil particles, thereby lowering the fruiting position and resulting in sparse fruiting, abnormal fruiting positions, and an increase in soil-level mushrooms.

Preventive measures: 1. When spreading the compost, thoroughly pick out any soil clods mixed into it. 2. Case the soil evenly, and apply the 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 mycelial cultivation stage 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 encourage the mycelium to grow into the soil layer, raise the mycelial growth position, and spray the fruiting water properly and in a timely and appropriate amount to prevent early fruiting and too low a fruiting position.

Hollow-stemmed white-core mushrooms

Symptoms: The tissue of the button mushroom stem is not solid, and a white, loose pith appears inside. After the mushroom body dries or is cooked, the pith shrinks or falls away, forming a hollow center.

Causes: This is mainly due to improper water management. If the air humidity in the mushroom house is low and the soil layer humidity is low, especially if the water content of the coarse soil layer is insufficient, the rapidly growing fruiting bodies cannot obtain sufficient water from the soil layer, and the transport and supply of nutrients will also be reduced. In addition, the mushroom body itself continuously evaporates water, causing a shortage of water in the middle of the stem and loose tissue, thus producing the hollow-stemmed white-core phenomenon.

Preventive measures: 1. When watering the coarse soil and spraying the fruiting water and mushroom-emergence water, the amount of water should be sufficient to prevent the soil particles from only appearing wet on the surface. 2. After fruiting begins, spray mushroom-emergence water as much as possible once to ensure that the coarse soil layer can continuously receive water supplementation 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, so as to prevent water from dissipating too quickly.

Hard opening of the caps

Symptoms: Before the button mushroom fruiting bodies have matured, the cap and stem separate and split open, exposing the pale red gills.

Causes: This is mainly due to a sharp change in temperature (temperature below 18 degrees Celsius, with a temperature difference of about 10 degrees Celsius), which creates a temperature contrast between the compost temperature, the soil layer temperature, and the air temperature. The nutrient metabolism and physiological metabolism of the mushroom stem become disordered, causing the stem rooted in the soil layer and the cap exposed on the soil surface to crack due to 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, adjust the relative air humidity well to promote balanced growth of all parts of the mushroom body.

Thin-skinned early opening

Symptoms: The fruiting bodies have thin stems and thin caps, and open prematurely.

Causes: Excessive fruiting density, relatively high mushroom house temperature, insufficient relative air humidity, relatively dry casing soil on the bed surface, and rapid fruiting body growth can all lead to thin-skinned early opening.

Preventive measures: Properly control the fruiting position. Ventilation in the mushroom house should preferably be done in the early morning and evening to lower the mushroom house temperature, and appropriately increase the moisture of the bed surface soil layer and the relative air humidity.