Spring Cultivation Techniques for Shiitake Mushrooms and Common Pest and Disease Control Methods
When cultivating shiitake mushrooms in spring, pay attention to the following points:
1. Block selection. Thoroughly dry the fully colonized shiitake blocks and logs, and select uncontaminated, intact blocks or logs for processing. If the old mycelial skin is too thick, scratching can be done, and they can be used only after the mycelium has healed.
2. Soaking. Soaking blocks in hot water is an ideal method for inducing budding in spring-cultivated shiitake mushrooms. When soaking the blocks, heat the water to 33°C, then pour the shiitake blocks or logs into the pool and soak for 3-5 hours. If the water temperature drops, add boiling water to adjust the water temperature to 18°C-33°C. Then remove the soaked shiitake blocks, place them at the fruiting site, and cover them with plastic film to maintain temperature until buds appear on the blocks, then carry out ventilation and air exchange. During the fruiting period, if the air temperature is low, hot water at 18°C-33°C can be sprayed directly onto the blocks, then cover with plastic film to raise the temperature of the environment inside the film, so as to facilitate normal growth of the shiitake mushrooms.
3. Harvesting of shiitake mushrooms and nutrient supplementation for the blocks. After the soaked blocks are covered with film, continue to keep them warm. The mushroom buds can quickly push out of the blocks. At this time, strengthen ventilation and raise the air temperature. The first flush of mushrooms can be harvested in 10-17 days. After harvesting, uncover the film and let the shiitake blocks dry thoroughly for 7-15 days, then soak them a second time in hot water. After the second flush is harvested, certain nutrients should be supplied to the shiitake blocks. Commonly used nutrient substances include: triacontanol solution, 30 ppm citric acid solution, 0.2% monopotassium phosphate and glucose solution, less than 0.2% urea, soybean milk, rice washing water, mushroom growth hormone, etc.
Common pests and diseases of shiitake mushrooms include three categories: competitive mold contamination, insect pests, and diseases. They are major enemies in shiitake production and directly affect the effectiveness of spawn production and cultivation. Therefore, adhere to the policy of “prevention first, combining prevention and control.” Once pests or diseases are found, carefully analyze the causes, take control measures early, and thoroughly eliminate or suppress their spread. When chemical control is truly necessary, it should be carried out before fruiting or after harvesting is completed. Never spray directly onto the mushroom bodies, so as to avoid residual toxicity affecting human health.
I. Control of Common Competitive Molds
1. Trichoderma viride:
Trichoderma spp. is one of the most common and most harmful competitive molds in shiitake production. Green mold mycelium grows densely, initially white, gradually producing green spores, with the center of the colony dark green, causing the entire substrate to turn dark green.
Green mold is suited to growth at 15-30°C and in slightly acidic environments. Green mold competes with shiitake mycelium for nutrients. In severe cases, it turns the entire substrate green, causing foul odor and softening, leading to rotten logs.
Control methods: Remove sources of competitive mold, maintain ventilation for the long term, and purify the environment; keep the mushroom shed dry; keep the substrate moisture content appropriately on the dry side; inoculate at the proper time; do not use acidic agents such as formaldehyde for too long or in too large amounts, so as to avoid creating an acidic environment; strictly follow sterile procedures during inoculation; prevent high temperatures when stacking bags; during the bag-removal fruiting period, prevent excessive watering and pay attention to ventilation in the mushroom shed.
Once discovered, if it is spawn, it must be discarded immediately. If it is a mushroom log, inject the affected area with a mixture of 2% formaldehyde and 5% carbonate or with 1-2% Lysol, 0.1% thiophanate-methyl, 0.1-0.2% zineb, or similar agents. If discovered after bag removal, apply 0.2% carbendazim solution to the affected part and its surroundings, and the next day apply 5% lime water to the affected area. If more than 1/3 is affected, cut off the infected part with a knife, and apply or soak the cut surface with 500-fold Bordeaux mixture for disinfection.
2. Neurospora: commonly known as red bread mold, it is one of the most common competitive molds. It is initially white and powdery, later fluffy, changing from pale yellow to orange-red.
Neurospora is a soil microorganism. At 25-30°C it germinates when moisture is present and spreads rapidly. It is a major harmful mold during inoculation and the mycelial growth period, with extremely strong transmission ability.
Control methods: Strictly control pollution sources. Select fresh sawdust, wheat bran, etc. for raw materials; remove microporous bags when selecting plastic bags; clear away surrounding garbage; add 50% carbendazim when mixing ingredients, blending it in at 0.1-0.2%; sterilize the substrate thoroughly; for inoculation, wipe and disinfect bags with alcohol mixed with carbendazim; keep the mycelial growth site dry and clean; during the bag-removal fruiting period, prevent excessive watering and pay attention to ventilation.
Once discovered, if it is spawn contamination, discard it immediately; if it occurs on mushroom logs, spread the bags to dissipate heat and sprinkle lime powder; at the same time, apply diesel oil to the affected area. Never throw it around or leave it improperly, as this contaminates the space.
II. Control of Common Insect Pests
1. Springtails: After entering the hot and humid season in May, the biggest pest during fruiting is springtails, which directly affect exports. Springtails are black-gray and occur under high temperature above 25°C and humidity above 85%. They are not easy to remove. Control measures are: lower the shed temperature and reduce humidity (a water content of about 40% inside the mushroom logs is appropriate); place 80% dichlorvos 1000-fold solution mixed with a few drops of honey on the ground to trap and kill them; spray 50% phoxim diluted to 500-fold for poisoning and killing; spray 0.1% derris extract or 200-fold pyrethrum solution (deltamethrin is also acceptable); sprinkle lime powder on the ground and walls; spray pesticide on some weeds and branches inside the shed to kill them.
2. Nematodes: The nematodes harmful to shiitake mushrooms are mainly rhabditid nematodes. They are pink, resemble earthworms, and have a body length of about 1 mm. They are mainly introduced from the substrate and water sources.
Control methods: Sterilize the substrate thoroughly, keep the water source clean, avoid over-wet watering, and ventilate frequently. When nematodes occur, spray with 5% lime water or 1% salt water several times, and at the same time sprinkle lime powder on the ground for disinfection.
III. Control of Common Diseases
1. Deformed mushrooms: Big-foot mushroom — the stipe is thick and short, and the cap is thick and fleshy. The main cause is that high-temperature varieties are made into logs relatively late, and low temperatures during fruiting affect formation. Control measures mainly involve selecting varieties that meet temperature requirements and reasonably arranging the production season. Hollow-stipe mushroom — the stipe is hollow and soft, the cap is small, and fruiting is dense and clustered. The cause is severe water loss from the logs, relatively low air humidity, and relatively high temperature, leading to dehydration and hollowing of young mushrooms. Control measures mainly involve timely water supplementation after each flush is harvested, and moving them to disturb the buds and supplement water. Snail-cap mushroom — the cap is about the size of a field snail. The causes are that high-temperature varieties are not yet physiologically mature but are induced to bud and fruit under low-temperature conditions; low-temperature varieties are not yet physiologically mature but are induced to bud and fruit under high-temperature conditions; and there is too much nitrogen source in the substrate. Control measures mainly involve treating the symptoms, identifying the cause, arranging the fruiting period well, and promptly removing snail-cap mushrooms to preserve nutrients, then fruiting again when the temperature is suitable.
2. Wilting and rotting mushrooms: Wilting and rotting occur during the bud stage, mainly due to excessive humidity in the mushroom shed, invasion by competitive molds causing mushroom rot, and in some cases viral damage causing mycelial degeneration, resulting in rotting of the fruiting bodies, and excessively high carbon dioxide content, etc. Control methods: regulate temperature and prevent damage from high temperatures; control humidity, keeping the relative humidity in the mushroom shed at about 90% and the water content of the mushroom logs at about 60%; inspect frequently, remove roots, and apply lime water or benzalkonium bromide locally.