Key Technical Points for Autumn Management of Shiitake Mushroom Bag Cultivation

Shiitake mushrooms have a long fruiting period, spanning three seasons - autumn, winter and spring - about 10 months. Generally, inoculation is done in August to September, and fruiting occurs in November to December. Shiitake mushrooms that grow before December are called autumn mushrooms. In shiitake mushroom bag cultivation, autumn management is very important. The key techniques are as follows:

1. Indoor mycelium incubation. It takes more than 60 days from inoculation to physiological maturity for shiitake mushrooms. After inoculation, they should be promptly moved into the incubation room for culturing. The bags are arranged in a "well" pattern, stacked 8 to 9 layers high, with the room temperature controlled at around 25°C and relative humidity kept below 70%. From 1 to 6 days after inoculation, the mycelium is in the recovery and germination stage, and the room temperature can be controlled at 28 to 30°C. During this period, the bags must not be turned, ventilation should be avoided, and shading should be used to create dim light. From 7 to 10 days, the mycelium begins to grow and colonize the substrate, and the room temperature is lowered to 26 to 28°C, with ventilation 2 to 3 times a day. On the 7th day, carry out the first stacking rotation, that is, swap the positions of the stacked bags from top to bottom and from inside to outside, so that every bag can receive management under the same conditions. When turning the stacks, handle them gently, strictly preventing damage to the seals and infection by contaminant microorganisms. At the same time, carefully inspect for contaminant contamination while turning the stacks. If pinpoint contaminants appear, inject a mixture of 50 milliliters of 75% alcohol and 30 milliliters of 25% formaldehyde to seal the affected area. If contaminants appear on the inoculation block or around it, dig out the contaminated part and re-inoculate. If contamination is on the sealing material, dab the affected area with 0.2% potassium permanganate or carbendazim. After 11 to 15 days, the mycelium grows vigorously and has extended to 4 to 6 cm. The room temperature should be maintained at 24°C, and ventilation should be increased for the second stacking rotation. One day later, use a bamboo skewer to make holes to increase oxygen, piercing 4 slanted holes around the extending mycelium. The bag temperature should be controlled at 20 to 24°C and must not exceed 26°C. After 50 days, remove the shading materials from doors and windows to promote mature and robust mycelial growth.

2. Bag color change. The timing and quality of color change affect both the timing of fruiting and the yield. After the mycelium reaches physiological maturity, it changes from white to reddish-brown, and yellow droplets appear, followed by the emergence of shiitake mushroom primordia. During the color change period, increase diffused light in the room, strengthen ventilation, and open and cover the plastic film intermittently to create an alternating dry and moist environment that promotes color change.

3. Outdoor fruiting induction. Shiitake mushrooms are a low-temperature, temperature-variable fruiting type of mushroom. After the bags change color to a reddish-brown mycelial film, move the bags to a shaded outdoor area, cover them top and bottom with wheat straw, and sprinkle water to retain moisture. Cover with film at night and uncover during the day, repeating for 4 to 5 days, then cover with plastic film to induce fruiting by keeping the bags sealed.

4. Fruiting management. In autumn, temperatures gradually decline, which is favorable for robust mycelial growth. Three days after fruiting induction, pick out the fruiting bags once a day and place them on the shelves in the mushroom shed, with a bag spacing of 7 to 10 cm, until fruiting induction is entirely complete. After the bags are placed on the shelves, use a sharp knife to slit the plastic film around the mushroom buds to promote mushroom resting. Generally, during the 7 to 10 day resting period, do not cover with film. When the young mushrooms are the size of peanut kernels, flower formation can be induced.

5. Management during the flower induction period.

(1) Humidity. Maintain the relative humidity inside the bags at 80% to 90%, keep the temperature at 12 to 18°C, and provide relatively abundant diffused light and good ventilation. If humidity is too high, first drain moisture, then uncover the film for 1 hour before covering again, and light a stove to expel dampness. If it is dry, place a pot on the stove to add water, and cover with plastic film to raise the shed temperature to 28°C. If water drips from the shed film and the young mushrooms become damp, open the doors and windows and light a stove to expel dampness.

(2) Temperature. Because shiitake mushrooms have the characteristic of fruiting under variable temperatures, artificially increasing the temperature difference and alternating dry and wet conditions can force the caps to crack and form flower mushrooms. Therefore, cover with film during the day to let sunlight through and raise the mushroom shed temperature to 28°C. After 12 midnight, open the film to let cold air enter, so the day-night temperature difference can reach more than 10°C. For 3 to 4 consecutive days, this can stimulate the massive occurrence of flower mushrooms.

(3) Alternating dry and wet conditions. After moistening to induce buds, when the mushrooms grow to 2 to 3 cm, choose a sunny midday to splash water on the ground surface to accelerate fruiting body growth, then uncover the film at night to let cold air stimulate them and dry the caps, then cover with film again, using ground warmth and ground moisture in coordination with alternating dry and wet conditions to promote the caps to split into patterned flower mushrooms.