Methods and Technical Key Points for Controlling Pests and Diseases of Oyster Mushrooms
In oyster mushroom cultivation, pests and diseases are a stumbling block. Recognizing and promptly controlling them is of great significance for normal production.
Once pests and diseases are discovered, if measures are not taken in time, they will seriously affect oyster mushroom yields and sometimes cause total crop failure. Therefore, superior and highly resistant strains should be selected, scientific management should be strengthened, and environmental conditions that favor the growth of the mushroom fungus while disfavoring the reproduction of pests and diseases should be created, so as to prevent trouble before it happens. The following are introductions to the control methods for some common pests and diseases:
1. Diseases
Diseases commonly fall into the following two categories:
(1) During the cultivation process, improper environmental conditions and management methods cause abnormal physiological activity. We call this physiological disease.
Overgrowth of mycelium: The surface aerial mycelium is dense, affecting mushroom formation. The main cause of overgrowth of mycelium is high air humidity and poor ventilation. The preventive method is to strengthen ventilation and lower the humidity.
Big-foot oyster mushroom: The cap of the fruiting body is extremely small, and the stipe is thick and long. This is mainly caused by lack of oxygen and poor ventilation. It can be prevented simply by strengthening ventilation and paying attention to light.
Oyster mushroom wilting: Mushroom buds or fruiting bodies stop growing, gradually shrink, dry up and die, and rot. The main causes are insufficient moisture and excessive ventilation. The preventive method is to increase the relative air humidity, keep the bed surface from drying out, and when ventilating, never let the wind blow directly on the mushroom buds or fruiting bodies.
Oyster mushroom pesticide damage: After the fruiting bodies are sprayed with pesticide (dichlorvos), the caps stop growing, and a black edge forms at the margin and curls. The use of certain harmful pesticides must be prohibited.
Rust spots: Rust-brown spots appear on the caps and stipes of oyster mushrooms. The main causes are poor ventilation and excessive humidity. The preventive method is to strengthen ventilation and lower the humidity.
(2) The fruiting bodies are contaminated by other miscellaneous fungi, causing disease or death. We call this infectious disease.
A common disease of oyster mushrooms is dry bubble disease (brown spot disease), which mainly harms their normal growth. Its symptoms are white cottony mycelium on the surface of the fruiting bodies, the appearance of brown spots, and shrinkage and cracking of the caps.
Control method: Lower the temperature and strengthen ventilation. Spray the diseased area with 2% formaldehyde solution or 1:500 carbendazim.
2. Miscellaneous fungi
There are many miscellaneous fungi harmful to dried mushrooms, mainly the following:
(1) Penicillium and Trichoderma: Penicillium is white at first and later turns light green. Trichoderma is green from the beginning, and the green gradually deepens afterward. High humidity, poor ventilation, and an acidic environment make them prone to occur.
Control: The contaminated parts can be dug out, then sprinkled with carbendazim powder or quicklime. If contamination occurs within the substrate, it should all be burned or deeply buried.
(2) Neurospora: The conditions for its occurrence are a temperature of 25°C to 30°C, under which spores germinate in 6 hours, forming large amounts of cottony mycelium, and after 48 hours produce large amounts of pink conidia.
When preparing the culture substrate, mixing in 1:500 carbendazim or meixiujing can prevent its occurrence. If it occurs, destroy or deeply bury it as early as possible.
(3) Gypsum-like mold: It often occurs on the surface of the culture substrate, producing powdery, dense white mycelium.
Control method: Increase the phosphorus fertilizer content of the substrate and spray a 1:7 acetic acid solution.
(4) Aspergillus flavus: The mycelium is white at first and later produces large amounts of yellow spores. Under high temperature (above 27°C) and when the culture substrate moisture is on the dry side, it occurs severely.
Control method: Lower the temperature and keep it below 25°C, and when preparing the culture substrate, keep the moisture suitable.
3. Insect pests
(1) Mushroom maggots: They mainly harm the mycelium or fruiting bodies. The larvae of mushroom flies, mosquitoes, and the like are all white or yellow legless small maggots that bore into and feed on the fruiting bodies. Control method: Remove aged mycelium; take advantage of the phototaxis of adults by setting up insect-killing lamps for trapping and killing, or spray highly effective and low-toxicity pesticides, such as a 1000-fold dilution of trichlorfon, which can kill larvae and eggs.
(2) Mushroom mites: These are some small insects belonging to the class Arachnida and order Acari. They are very small, yellow-white, and light yellow-brown when in piles, like dust or rice bran. They have strong reproductive capacity and move quickly, feeding on mycelium and caps, causing mushroom buds to wilt.
Control: Fully sun-dry the raw materials, spray dichlorvos in the surrounding environment, and after occurrence spray a 800-fold dilution of 4% dicofol emulsion.
(3) Springtails: The adults have flexible tails and jump like fleas, biting and eating the fruiting bodies. Control method: Spray 0.1% derris extract.
There are also some pests such as slugs, ants, cockroaches, and mole crickets. During control, some quicklime can be scattered on the ground.
4. Treatment of old mushroom houses
Continuous cultivation of oyster mushrooms indoors or in tunnels often causes severe damage from pests, diseases, and miscellaneous fungi, leading to failure. This results in high yield in the first cultivation, severe contamination in the second and third, and even no harvest. The reasons are: no disinfection after each cultivation, harmful metabolic products produced during the growth of oyster mushrooms accumulate on the bed frames and tunnel walls. Aging of the mycelium, and the darkness, dampness, and poor ventilation of the room or structure cause the breeding of miscellaneous fungi and the rampant spread of insect pests.
Control method: Pay attention to environmental sanitation, wash and scrub the walls clean with 5% to 6% alkaline water, scatter quicklime on the ground, or spray carbolic acid to eliminate miscellaneous fungi. In addition, spray insecticides to eliminate harmful insects. Use formaldehyde, sulfur, and other chemicals for sealed fumigation and disinfection.
5. Measures to prevent allergy to oyster mushroom spores
Oyster mushrooms should be harvested promptly after maturing. Harvesting after the spores have been released not only affects the formation of the next flush of mushrooms, but also seriously harms the health of workers.
Oyster mushroom spores can cause allergic reactions in most people, causing symptoms such as coughing, sticky phlegm, chest tightness, and low fever.
Preventive method: Harvest promptly. After maturing, harvest promptly before the spores are released. Before workers enter the mushroom house, first spray atomized water so that the spores settle to the ground with the water droplets, reducing the spore content in the air.
In addition, relevant materials introduce that when the caps are 2 to 3 cm, spray sodium glutamate nutrient solution as a top dressing. The formula is: water 100 jin, sugar 1 jin, sodium glutamate (monosodium glutamate is also acceptable) 0.1 jin, vitamin B1 100 tablets. Spray once a day. This can increase yield and delay the time of spore release.
If the human allergic reaction is severe, one should stay away from the original work for four months.