Causes and Control Methods of Deformed Mushrooms in Greenhouses

1. Hollow white-stem mushrooms. The mushroom stems become loose and white, and in severe cases shrink to form a hollow center. Causes: during the fruiting body growth stage, it is caused by dry air and high temperatures. When the relative air humidity is below 85%, the water content of the casing soil layer is relatively low, and the temperature inside the mushroom house is above 18°C, the mushrooms grow quickly and evaporate water quickly, causing the water absorbed by the mushroom body to be less than the water lost through transpiration. Control methods: spray water promptly during the day to keep the relative air humidity at 90%, and ventilate promptly after spraying water in the morning and evening to lower the greenhouse temperature, keeping it at 14-18°C.

2. Hard veil opening: the universal veil separates from the stem, and the cap opens too early, resulting in poor market quality. Causes: in the early fruiting stage, a sudden drop to low temperatures, a sharp fall from high temperatures, and a large temperature difference cause the mushroom house temperature to be too low. Control methods: strengthen insulation measures for the mushroom greenhouse, pay attention to weather changes, reduce the temperature difference, and keep the relative air humidity inside the mushroom house within the appropriate range.

3. Dead mushrooms. During the fruiting period, young mushrooms wilt and turn yellow, stop growing, and finally die; in mild cases they die in patches, and in severe cases an entire flush dies. Causes: (1) Temperature too high. High temperatures in late autumn and early spring cause nutrients in the mushroom body to flow backward, leading to death from nutrient deficiency; (2) After casing, the mycelium grows too fast and fruiting is too dense, so nutrients cannot be supplied adequately, causing young mushrooms to die from malnutrition; (3) The mushroom house is not ventilated in time, oxygen is insufficient, and carbon dioxide concentration is high; (4) The mushroom greenhouse temperature is relatively high (above 20°C), humidity is too high (above 95%), and ventilation is not timely after watering, so water accumulates on the mushroom surface, causing the small mushrooms to suffocate and die from lack of oxygen. Control methods: manage the sowing time properly to prevent fruiting during high-temperature seasons; do not sow too much, to prevent overly vigorous mycelial growth and overly dense fruiting that causes nutrient deficiency; do not let the water content of the casing soil layer be too high, lower the fruiting position, avoid overly dense fruiting, and at the same time ventilate promptly while watering to cool down, preventing water from accumulating on the mushroom surface.

4. Thin-skinned opened-cap mushrooms: the stems are slender, the caps are thin, and the caps open early. Causes: during the peak fruiting period, the temperature inside the mushroom house is above 20°C, the relative air humidity is too high, ventilation is poor, and in addition the mushrooms on the bed surface fruit densely and quickly, competing with one another for oxygen and nutrients. Control methods: the cultivation substrate must be thoroughly fermented, ventilate promptly after watering, prevent water from accumulating on the mushroom surface, and keep the mushroom greenhouse temperature suitable.