What to Do About Abnormal Mycelium Growth in Edible Mushrooms? Cause Analysis and Preventive Measures

I. Mycelium turning yellow and shrinking: 10-15 days after inoculation, the mycelium gradually turns yellow, becomes sparse and shrinks, and cannot continue growing into the substrate.

1. Causes: ① The temperature in the cultivation room is high and ventilation is poor; the bags are placed too tightly together, which hinders air circulation and makes it difficult for substrate heat to dissipate, so the mycelium is damaged by high temperatures. ② The substrate is too wet and packed too firmly, so air permeability is poor and the mycelium is deprived of oxygen. ③ Sterilization is incomplete, so thermophilic bacteria multiply in large numbers in the substrate, competing for nutrients and inhibiting mycelial growth. ④ Ventilation in the cultivation room is poor, resulting in a high carbon dioxide concentration.

2. Preventive measures: ① It is best to keep the temperature of the cultivation room at around 20°C. There should be a slight gap between bags to help substrate heat dissipate. In hot weather, ensure good ventilation and cooling. ② Master the substrate-to-water ratio properly. Fill the bags to an appropriate firmness; if the substrate is found to be too wet, the bags can be moved to a well-ventilated place, and for bags whose mycelium has grown past the shoulder, the tying rope can be loosened to allow ventilation and reduce moisture. ③ For atmospheric-pressure sterilization of the substrate, maintaining 100°C for 10 hours can prevent bacterial contamination.

II. In the late stage of mycelial growth, the mycelium grows slowly and does not fill the bag for a long time

1. Causes: ① The inside of the bag is not breathable and the mycelium is deprived of oxygen, which is mostly seen in closed-type mycelial cultivation with both ends tied shut. ② The temperature is too low, so the mycelium grows very slowly or stops growing.

2. Preventive measures: ① When using closed-type mycelial cultivation, once the mycelium has grown 3-5 cm into the substrate, untie the ropes at both ends of the bag and loosen the bag opening to let air in, or use puncture ventilation to supplement oxygen. ② Maintain cultivation at a suitable temperature, with the indoor temperature not lower than 18°C.

III. Mushrooms fruiting before the mycelium has fully filled the bag

1. Causes: The temperature during mycelial cultivation is too low, and the temperature is suitable for fruiting.

2. Preventive measures: Cultivate at the proper time; during low-temperature cultivation, heat the mycelial culture so that the temperature is maintained above 18°C.

3. Control methods: ① Run mycelial growth at the proper time to shorten the mycelial growth period and reduce water evaporation from the substrate surface; ② Open the bag mouth at the proper time; ③ If the substrate surface is found to have lost water, replenish water in time.