What to Do When Straw Mushroom Mycelium Shrinks? Causes and Control Methods

1. Using inferior spawn: Spawn that is too old or too young, degenerated spawn, weak mycelial vitality, poor stress resistance, or spawn stored for a long time in environments with temperatures that are too low or too high can all lead to failure to germinate after spawning and shrinkage of mycelium in the spawn blocks.

Control: Select spawn of the appropriate age and high quality, and ensure the temperature during the cultivation process does not get too low.

2. Improper control of compost temperature: When the air temperature is high, the compost is too thick, and the mushroom house has good insulation, the temperature inside the compost after spawning exceeds 42°C for an extended period, which causes mycelium to shrink and die, resulting in burning of the mycelium; when the temperature is too low or the day-night temperature difference is too great, it can also cause slow mycelial growth and shrinkage. Generally, during the mycelial growth stage, the compost temperature should not remain below 30°C for extended periods. Below 28°C, although the mycelium will grow, the yield will not be high, and it may even fail to produce mushrooms.

Control: After spawning, pay close attention to the temperature inside the mushroom house and the compost temperature. If the temperature is too high, ventilate to cool it down; you can also spray the air space or run water underground. When the temperature is low, insulate and heat promptly.

3. Improper control of compost moisture: When cultivating straw mushrooms, abnormal mycelial growth caused by compost that is too dry rarely occurs. However, if the water content is too high, exceeding 75%, or if the plastic film is covering too tightly so that the compost is not breathable, combined with poor ventilation in the mushroom house, the mycelium will shrink or self-digest due to lack of oxygen and other reasons.

Control: Handle the compost according to the principle of preferring dry over wet, and appropriately increase the amount of water sprayed when applying the "fruiting water."

4. Improper watering adjustment: When adjusting water, if the water temperature is too low, the water flow is too forceful, the water volume is too large, the mushroom buds are too small, or ventilation is not timely, it causes mycelium to shrink and die.

Control: When adjusting water, the water temperature must be above 25°C. If the compost temperature is on the low side, the water temperature should preferably be above 30°C.

5. Damage from competing microorganisms and pests: Competitive microorganisms compete with straw mushroom mycelium for nutrients. Pests such as nematodes, mites, and mushroom fly larvae will feed on the mycelium and cause infection by competing microorganisms and viruses, leading to mycelial shrinkage and death.

Control: Secondary fermentation must be thorough; kill the competing microorganisms and pests inside the mushroom house; select superior spawn; maintain environmental sanitation around the mushroom house.

6. Phytotoxicity: After spawning, some mushroom growers, in the process of preventing and controlling diseases and pests, cause phytotoxicity that leads to mycelial shrinkage and death due to improper operations such as using the wrong medication, excessive concentration, or excessive dosage, or because the water-spraying container previously held pesticide and was not washed clean, or because excessive urea was added to the compost, producing high-ammonia compost.

Control: Before using any medication, be sure to treat the specific problem and read the instructions carefully; containers used for spraying water must be kept separate from those used for spraying pesticides.