Management Methods and Technical Key Points for Shiitake Mushrooms During the Fruiting Period

After the shiitake mushroom logs change color, the mycelium is fully mature and has accumulated rich nutrients. Under the stimulation of certain conditions, it rapidly transitions from vegetative growth to reproductive growth, initiating the differentiation and development of fruiting body primordia, which marks the beginning of the fruiting period.

I. Promoting bud formation: Shiitake mushrooms are a type of fungus that fruits under variable temperatures. A certain temperature difference, scattered light, and fresh air are beneficial to the differentiation of fruiting body primordia. During this period, the covering film on the beds is generally removed, and the temperature in the fruiting greenhouse should preferably be controlled at 10-22°C, with a day-night temperature difference of 5-10°C. If the natural temperature difference is small, the temperature difference can be artificially enlarged by taking advantage of daytime and nighttime ventilation. The relative air humidity should be maintained at around 90%. When conditions are suitable, white cracks will appear on the brown mycelial film on the surface of the logs within 3-4 days, and mushroom buds will soon grow out. During this period, it is necessary to prevent excessively low spatial humidity or insufficient water in the logs, so as not to affect the formation of fruiting body primordia. When such situations occur, increase water spraying. After each spraying, air the logs until the surface is no longer sticky and slippery but only slightly moist, then cover with plastic film to retain moisture. It is also necessary to prevent high temperature and high humidity to avoid contamination by miscellaneous bacteria and rotting of the logs. Once high temperature and high humidity occur, increase ventilation to lower the temperature and humidity.

II. Management during the fruiting body growth and development period: After the mushroom buds differentiate, they enter the growth and development period. The temperature for fruiting body growth and development differs among shiitake mushroom strains of different temperature types. Most strains can grow and develop fruiting bodies within a temperature range of 8-25°C, with the optimum temperature being 15-20°C. Under constant temperature conditions, the fruiting bodies grow and develop very well. The relative air humidity should be maintained at 85%-90%. As the fruiting bodies continue to grow, respiration intensifies and carbon dioxide accumulation accelerates, so ventilation should be strengthened to keep the air fresh, and a certain amount of scattered light is also needed. For shiitake mushrooms sown in summer, the initial fruiting period occurs in autumn. In northern China, autumn has clear skies and crisp air, a dry climate, and large temperature fluctuations. The logs have just begun to fruit, with sufficient water and rich nutrients, and the mycelium is robust. The focus of management is temperature control and moisture retention. In early autumn, when temperatures are high, shade materials should be added to the fruiting greenhouse, along with ventilation and water spraying to lower the temperature. In late autumn, when temperatures are low, light exposure should be increased during the day to raise the temperature. If strong light affects fruiting, shade nets can be hung in the middle of the greenhouse, and insulation curtains added at night. When spatial relative humidity is low, water spraying should mainly target the walls and air space to increase relative air humidity. When the fruiting bodies have grown to the point where the mycelial film has broken, the cap has not fully expanded, the edges are curled inward, the gills have all elongated and turned from white to brown, the fruiting bodies are at eight-tenths maturity and can be harvested. When harvesting, hold the log with one hand and grasp the base of the stipe with the other hand, twisting and pulling it off. After the entire first flush of mushrooms has been harvested, ventilate thoroughly once. On sunny days with dry weather, ventilate for 2 hours; on cloudy days or when humidity is high, ventilate for 4 hours to dry the surface of the logs, then stop water spraying for 5-7 days. Allow the mycelium to fully recover and grow. When the mycelium at the indentations left by harvested mushrooms turns white, replenish water to the logs. The water replenishment method is as follows: first, use No. 10 iron wire to poke a hole in the center of each end of the log, reaching a depth of 1/2 the length of the log, then poke 3 holes at equal distances on the sides of the log. Then arrange the logs in a soaking pool, place wooden boards on top of the logs, weigh down the boards with stones, and add clean water to soak for about 2 hours, until the water has soaked through the logs (the weight of the logs is slightly less than before fruiting). Logs that are not soaked through have insufficient water, while excessive soaking can easily cause the logs to rot, both of which affect fruiting. After water replenishment, rearrange the logs in the beds and repeat the previous management methods for promoting bud formation and fruiting, in preparation for the second flush of mushrooms. After the second flush is harvested, again stop watering and replenish water, repeating the previous management. Generally, 4 flushes of mushrooms are produced. Sometimes when the moisture content of the substrate is on the high side and the temperature and humidity during fruiting are suitable, the water loss from the logs during the first flush is not significant, so instead of the soaking method, water can be replenished by stopping watering for 5-7 days after the first flush is harvested, waiting for the mycelium to recover growth, then directly spraying a large amount of water onto the logs to let them absorb it naturally and increase their water content, then repeating the previous management for promoting bud formation and fruiting. After the second flush is harvested, soak the logs to replenish water. The soaking time can be appropriately longer. Thereafter, each time a flush is harvested, replenish water once.

In northern China, winter temperatures are low, fruiting bodies grow slowly, and yields are low, but the mushrooms have thick flesh and good quality. The focus of management in this season is heat preservation and warming. Increase light exposure during the day, add straw curtains at night, and if conditions permit, make a fire to raise the temperature. Ventilate at noon, and try to keep the temperature in the greenhouse above 7°C. Water can be sprayed on the air space and walls to regulate humidity, and less water should be sprayed directly on the logs. If the temperature is too low for fruiting, control the relative humidity of the greenhouse at 70%-75% and maintain the logs to overwinter.

Spring has a dry and windy climate. At this time, the logs have gone through autumn and winter fruiting. Due to significant water loss from the logs and insufficient moisture, mycelial growth is also less vigorous than in autumn. The focus of management is to replenish water to the logs, with a soaking time of 2-4 hours, frequently spray water on the walls and air space, and maintain relative air humidity at 85%-90%. In early spring, pay attention to heat preservation and warming. Ventilation should be appropriate and can be carried out after water spraying. Control the ventilation time and do not cause temperature and humidity to drop.