What are the key points of pollution-free cultivation techniques for edible fungi?
Pollution-free production environment
Spawn factories, incubation rooms, mushroom houses or mushroom sheds should all be built in places with high terrain, convenient drainage and irrigation, no factory pollution or garbage dumps nearby, and far away from livestock and poultry sheds, feed warehouses and toilets.
Pollution-free raw materials
The various raw materials for cultivating edible fungi, such as cottonseed hulls, straw, sawdust, bran, etc., should be dry, free from mildew and insect damage, and must not be contaminated or mixed with other pollutants. The chemicals used, such as gypsum, calcium carbonate, urea, etc., should be pure, and counterfeit or inferior products must not be used.
Substrate treatment
1. The substrate must undergo high-temperature fermentation. The substrate for cultivating button mushrooms, Agaricus blazei, shaggy ink cap mushrooms, etc. needs high-temperature fermentation. There are two methods of high-temperature fermentation: one-stage fermentation and two-stage fermentation. To ensure the quality of the substrate and increase the yield of edible fungi, the two-stage fermentation method is preferable. In the two-stage fermentation method, the substrate is piled outdoors for fermentation. When the temperature inside the pile rises to 65°C, it is turned. The fermentation time is 12-15 days, and it needs to be turned 3 times. This stage is called pre-fermentation. Then the pre-fermented substrate is moved into the mushroom house, piled on the bed frames, the doors and windows of the mushroom house are closed, and steam or coal fire is used to raise the temperature, so that the temperature in the mushroom house rises to 62°C within 2-6 hours and is maintained for 5-8 hours, after which the temperature is lowered to 50°C and maintained for another 4-7 days. This stage is called post-fermentation.
2. The substrate must undergo high-temperature sterilization. Many edible fungus substrates must undergo high-temperature sterilization before cultivation can succeed, such as shiitake mushrooms, white lingzhi mushrooms, yellow-back wood ear mushrooms, etc. High-temperature sterilization of the substrate is divided into two types: atmospheric pressure sterilization and high-pressure sterilization. Atmospheric pressure sterilization is to put the substrate into a steamer, and when the temperature in the steamer reaches 100°C, maintain it for 12-16 hours, using high temperature to achieve the purpose of sterilization; high-pressure sterilization is to stack the bagged substrate in a high-pressure sterilization pot, and when the temperature in the pot rises to 121°C-126°C, maintain it for 2 hours, using high temperature and high pressure to thoroughly sterilize.
3. Raw material cultivation. Some edible fungus substrates are directly cultivated without fermentation or sterilization, such as oyster mushrooms, enoki mushrooms, etc. However, raw material cultivation can only be carried out in the low-temperature season. In our province, raw material cultivation should be carried out after mid-October. At the same time, the substrate should be mainly cottonseed hulls, mixed with lime water, and no pesticides should be added.
Water requirements
The water used for cultivating edible fungi includes water mixed into the substrate, water sprayed in the mushroom house, and water used for soaking fungus logs. The water quality is required to be pollution-free, preferably meeting drinking water standards.
Pollution-free production of spawn
The environment for producing spawn, including the inoculation room, incubation room, spawn storage room and their surrounding environment, should be clean and hygienic, and far away from pollution sources. A spawn factory should have the basic equipment for producing spawn. The spawn production process should be standardized, and production should be carried out using the three-level expansion method. It is not allowed to expand stock spawn into stock spawn, or expand cultivation spawn into cultivation spawn. The production of mother spawn should control the number of subcultures, limited to 3-4 subcultures. The cultivated spawn should conform to the characteristics of the variety, be pure, have robust mycelial growth, be free from contamination by miscellaneous fungi and diseases and insect pests, and be of moderate age. Aged spawn, degenerated spawn, and spawn with weak growth or other undesirable phenomena should be discarded and not used.
Management during the mycelial growth period
Management during the mycelial growth period mainly involves controlling the temperature and humidity of the incubation room to create good conditions for mycelial growth. The suitable temperature for the mycelial growth of most edible fungi is 25°C-27°C. Therefore, 1-3 days after inoculation, the temperature should be controlled at 26°C-27°C, and afterward, as the mycelium grows, the indoor temperature should gradually be lowered to 22°C-25°C. The relative air humidity in the incubation room should be controlled below 70%. Within 7 days after inoculation, ventilate once a day for 20-30 minutes each time. After 7 days, increase the ventilation volume and extend the ventilation time. During the mycelial growth process, turn the pile once every 7-10 days to make the mycelial growth uniform. Because the mycelial growth speed accelerates, metabolic activity increases, and the mycelium's own heat production increases, if management is improper and the pile temperature rises, it is very easy to burn the mycelium to death. Attention should be paid to turning the pile and dispersing the fungus bags, while strengthening ventilation and lowering the indoor temperature. Within 1-5 days after inoculation is the dangerous period for contamination by miscellaneous fungi, and various effective measures should be taken to prevent contamination by miscellaneous fungi. The incubation room should be cleaned thoroughly and disinfected completely before materials are brought in. Lime should be scattered on the floor and walkways. After materials are brought in, disinfectant drugs should be sprayed regularly. Window screens should be installed on doors, windows and ventilation holes to prevent pests from entering and keep the air in the incubation room circulating.
Management during the fruiting period
During the fruiting period, conventional management methods are used, that is, adjusting temperature, humidity, light and other conditions so that all conditions are suitable for the growth and development of the fruiting bodies. However, hormones and chemical pesticides must not be applied during the growth of the fruiting bodies. After each flush of mushrooms is harvested, the dead mushrooms and residual mushroom fragments on the surface of the substrate and on the floor should be thoroughly removed, and the old mycorrhizae, fungal skin and pollutants on the substrate or casing soil should also be cleaned up. Contaminated fungus bags or waste materials should be treated far away from the mushroom house.
Pest and disease control
1. Purify the environment. Do a good job of sanitation in the incubation room, mushroom house and their surroundings, always keep them clean, and reduce the base number of pests and diseases in the environment to the lowest level.
2. Select excellent spawn. Spawn of suitable age with good yield performance, strong stress resistance, and robust and rapid mycelial growth should be selected. With such spawn, the mycelium germinates quickly and spreads rapidly, and in competition with miscellaneous fungi, it can first occupy the substrate surface and effectively inhibit the occurrence of miscellaneous fungi, pests and diseases.
3. Scientific management. In the process of edible fungus cultivation and management, every step should be operated in a standardized way. According to the characteristics of different mushroom types, create conditions suitable for their growth as much as possible, often observe the occurrence of pests and diseases, and achieve early detection and early control.
4. Integrated control. When pests occur, use trapping or manual capture methods for control as much as possible. Utilize the phototaxis of pests and use black light lamps and mosquito-killing lamps for trapping. To control fungus mites, bait trapping can be used. Fry rapeseed cake or other cakes, sprinkle them on gauze, or soak the gauze in sugar and vinegar liquid, then cover the affected area with the gauze. When the mites gather on the gauze to feed, remove the gauze and put it into boiling water to kill the mites. The effect is quite good after repeated control. Larger pests such as slugs and woodlice can be manually captured. Plant ash and tobacco powder can also be scattered on the affected area, which can prevent both disease and pest damage. In general, chemical drugs are effective in controlling pests and diseases, but when chemical pesticides are applied to edible fungi to control pests and diseases, drugs with high efficiency, low toxicity and low residue should be selected, such as carbendazim. However, chemical pesticides must not be applied during the fruiting period; they can be applied before fruiting or after harvesting the mushrooms.