Detailed Explanation of Methods for Preventing and Controlling Edible Mushroom Diseases and Pests

Bacterial Rust Spot Disease

I. Harmful Symptoms This disease often occurs on mushroom bags or mushroom beds, with mucus on the surface and yellowing mycelium; the pathogen can produce toxins, causing spots to appear on the caps. The spots are brown, round or oval, with a dark outer edge and irregular shape; when humid, the center of the cap is grayish-white with milky-white mucus; when the air is dry, the central part is slightly sunken. Spots on the stipe are diamond-shaped or oval.

II. Conditions for Onset Unsuitable climate, encountering high temperature and high humidity, with relative air humidity above 95%; poor ventilation, with carbon dioxide concentration above 0.1%; weak resistance of the mushroom spawn, and the disease will occur on a large scale. The pathogen can spread and cause harm through soil, water, air, compost, insects and manual operations.

III. Prevention and Control Methods (1) Cultivation control. Disinfect the mushroom yard and purify the water quality; strengthen ventilation in the mushroom yard to dissipate heat and lower the temperature, and never spray with large amounts of water; sow at the right time to avoid the high-temperature and high-humidity fruiting season. (2) For mushroom yards with a relatively high incidence of bacterial rust spot disease, when replanting, in addition to timely prevention and control, disease-resistant varieties should also be selected, and different high-yield and high-quality varieties should be rotated; varieties with relatively strong disease resistance should be selected. (3) Apply the right remedy. When the disease is mild, ventilate to dissipate moisture and spray 1% lime solution or 0.2% bleaching powder solution. If the disease is severe, first remove the diseased mushrooms, scrape off the yellowed surface mycelium, spray 5% lime solution, or dissolve one strong chlorine disinfecting tablet in 4 kg of water and spray, spraying 2 to 3 times in succession.

Bacterial Soft Rot Disease

I. Harmful Symptoms It is prone to occur during both the mycelial growth stage and the fruiting stage. If it multiplies in large numbers in the compost, it can form a yellow-brown and dark-colored mycelial layer, inhibiting mycelial growth. During the fruiting stage, after the fruiting body is infected, the mushroom body becomes water-soaked, sticky, and then rots.

II. Conditions for Onset The pathogen is widely present in organic matter and water. When unclean water is used during substrate mixing, the disease may infect during the mycelial growth stage. During the fruiting stage, if water accumulates at the mouth of the mushroom bag for a long time and the primordia are submerged, soft rot disease is likely to occur.

III. Prevention and Control Methods (1) Use clean water for mixing the substrate, appropriately control the moisture content of the compost during the mycelial growth stage, appropriately lower the air humidity in the mushroom house during the fruiting stage, strengthen ventilation, and prevent water accumulation in the mushroom bags when spraying. (2) Once diseased mushrooms are found on the mushroom bags or mushroom beds, remove them immediately, stop spraying water, and strictly prevent the spread of the pathogen. (3) For chemical control, refer to the prevention and control measures for bacterial rust spot disease.

Cephalosporium Soft Rot Disease

I. Harmful Symptoms The primordia at the affected site cannot form; after mushrooms have formed, the pathogen's mycelium can invade the stipe and cap of the mushroom body, and the affected mushroom body shows water-soaked soft rot; in severe cases, the mushroom body topples and rots.

II. Conditions for Onset The pathogen lives in soil rich in organic matter and in organic residues. The disease is likely to occur when fertile seedbeds, garden soil and surface soil are used; it occurs at a temperature of about 25°C, under acidic conditions, with relative humidity above 90%, in plastic greenhouses and solar greenhouses.

III. Prevention and Control Methods (1) Using subsoil or yellow mud soil as casing material can effectively reduce the source of disease. (2) Adopt an alternating dry-and-wet water management method for the mushroom bed, and maintain a good ventilation and air-exchange environment. During the transition between flushes, use 1% to 2% lime solution for prevention and control. (3) Once the disease occurs, suspend spraying, immediately ventilate to reduce humidity, and remove the diseased mushrooms. Spray the affected areas with 5% lime solution, or 50% carbendazim 800 to 1200 times dilution, or Duogufeng 500 times dilution for prevention and control.

Deformed Mushrooms

I. Causes Improper temperature management, or caused by toxic gases such as sulfur dioxide and carbon monoxide produced by heating with coal and firewood or straw.

II. Prevention and Control Measures The mushroom shed should have good ventilation and sufficient light; when increasing temperature in winter, pay attention to ventilation, do not light a stove fire directly inside the mushroom shed, and instead build a fire wall or fire flue.

Edematous Mushrooms

I. Causes The diseased mushrooms are basically normal in shape, but the mushroom body has high water content, appears semi-transparent, is yellowish in color, and drips water when held. The cause is improper water use and overly frequent watering, resulting in high humidity inside the shed, water accumulation on the caps that cannot evaporate, and ultimately an edematous appearance, or even softening and rotting.

II. Prevention and Control Measures Strengthen water management; when spraying water, ventilation and air exchange must be maintained, and do not allow water to accumulate on the caps; harvest at the right time, promptly remove diseased mushrooms when found, and at the same time strengthen ventilation and air exchange, adjust humidity well, and prevent the induction of other diseases and pests.

No Primordia Formation

I. Causes Improper selection of mushroom spawn, using low-temperature-type spawn in the high-temperature season or selecting high-temperature-type spawn in the low-temperature season; the moisture content of the compost is relatively low, and the surface of the substrate is dry; excessive vegetative growth, with vigorous mycelium on the surface of the compost; mycelial aging, with a thick mycelial film forming on the surface of the bag; poor ventilation and insufficient light, delaying the vegetative growth of the mycelium.

II. Prevention and Control Measures Select spawn of the appropriate temperature type, spray water to increase moisture, and raise the relative air humidity to 85% to 90%; appropriately reduce the nitrogen content when preparing the substrate to maintain nutritional balance, and lower the temperature when inducing primordia; use iron wire to scratch the mycelial film and prick holes to increase oxygen; ventilate and cool to widen the day-night temperature difference, spray water for stimulation, increase scattered light, and induce the formation of mushroom buds.

Soft Bags

Generally, mycelium grows on the surface of the bag substrate, but there is little mycelium inside the bag, sparse and not dense, and the mushroom bag is soft and lacks elasticity.

I. Causes Degeneration or aging of the spawn, with weakened vitality; high temperature damaging the mycelium; excessive addition of nitrogen, causing large numbers of bacteria in the substrate to multiply and inhibit mycelial growth; high moisture content of the compost and insufficient oxygen, affecting inward mycelial growth.

II. Prevention and Control Measures Select robust spawn of the right age. Inoculate at the appropriate temperature, culture at the appropriate temperature, and prevent high temperature from damaging the mycelium. Add an appropriate amount of nitrogen to the compost, and never overdose. When soft rot occurs in the mushroom bag, lower the temperature during the mycelial growth stage, prick holes in the bag wall to release moisture and increase oxygen, and appropriately extend the mycelial growth period so that the mycelium grows fully and thoroughly into the substrate.

Mushroom Burning

I. Causes When the temperature inside the compost reaches 35°C, the spawn does not germinate due to high-temperature culturing, or its germination ability is weak, mycelial growth stagnates, vitality declines, and it gradually yellows, shrinks, autolyzes, and finally the bag rots. Mushroom burning is a physiological disease more likely to occur in summer and autumn cultivation.

II. Prevention and Control Measures (1) The culture room should have good ventilation and air-exchange conditions, and the stacking method and stacking layers of the mushroom bags should be adjusted according to air temperature, substrate temperature and the temperature inside the mushroom bags, so that the room temperature and substrate temperature are not high. (2) Scientific management. Control the mycelial growth temperature at 20°C to 25°C, and turn the bags and turn the piles in time; ventilate and exchange air, and control environmental humidity well; culture in dim light, do shading work well, and prevent direct sunlight. (3) Once mushroom burning is found, take remedial measures in time. If the mushroom bag is not contaminated and the inoculum block has been burned to death, it can be re-inoculated; if the mushroom burning is relatively mild and the mycelium can recover growth, ventilate and cool to allow the mycelium to grow robustly; if the mushroom burning is severe and the compost is contaminated and deteriorated, it is best to dry the substrate in the sun for use in cooked-substrate cultivation.

Slugs

Slugs, also known as snot worms and sticky worms, are a type of mollusk. They mainly bite and eat the fruiting bodies of oyster mushrooms, can directly feed on mushroom buds, young mushrooms or mature fruiting bodies, and leave feces and white mucus trails near the affected areas.

Prevention and Control Methods: Keep the mushroom yard clean and hygienic, remove dead branches, fallen leaves and weeds, so that slugs have no hiding places; taking advantage of the slug's habit of hiding by day and coming out at night and causing harm at dusk and on cloudy and rainy days, carry out manual capture; scatter lime powder or spray dilute salt water, or spray 0.3% to 0.5% sodium pentachlorophenate aqueous solution, in places where slugs frequently enter and exit, which can repel and kill slugs and prevent them from invading.

Gall Midges

I. Morphological Characteristics The adult has a pointed head and small body, with a body length of about 1 mm. The larva has a body length of 3 mm, initially white, and orange-red or cream-yellow when mature.

II. Harmful Symptoms The larvae bite and eat the mycelium, causing the mycelium to decline. Biting and eating mushroom buds can cause the buds to wither and die, and the young mushrooms to develop poorly. They harm the stipe, gills and cap, causing the mushroom body to dry up and die.

III. Prevention and Control Measures (1) Use standard mushroom houses or plastic greenhouses, and install screen netting. Coordinate temperature, humidity, light and air. (2) Keep the inside and outside of the mushroom house clean and hygienic; sterilize the compost at high temperature, sun-dry it and pile it for fermentation to kill insect eggs and larvae. (3) During the peak emergence period of adults, use mosquito repellent to repel and kill them, and use black light lamps to trap and kill them. (4) Chemical control. Spray fenvalerate for prevention and control.

Sciarid Flies

I. Morphological Characteristics The adult is small, dark brown, with a body length of 2 to 4 mm. The larva has a black head and a milky-white body. The pupa is initially white, then gradually turns yellow-brown.

II. Harmful Symptoms The larvae move through the compost in search of food, can bite off and eat up all the mycelium, causing "mycelial regression," and making the substrate surface black and loose and crumbly. The fruiting body, when affected, turns yellow, dries up and dies.

III. Prevention and Control Measures (1) Use standard mushroom houses or plastic greenhouses, and install screen netting. Coordinate temperature, humidity, light and air. (2) Keep the inside and outside of the mushroom house clean and hygienic; sterilize the compost at high temperature, sun-dry it and pile it for fermentation to kill insect eggs and larvae. (3) During the peak emergence period of adults, use mosquito repellent to repel and kill them, and use black light lamps to trap and kill them. (4) Chemical control. Spray fenvalerate for prevention and control.

Phorid Flies

I. Morphological Characteristics The adult is black or black-brown, with a small head and large thorax, and a body length of 4 to 5 mm. The larva is maggot-like; the newly hatched larva is white or yellow-white and small in size, and the mature larva has a body length of about 4 mm.

II. Harmful Symptoms The larvae harm the compost, mycelium and fruiting bodies, causing the mycelium to shrink and decline, the mushroom buds to wither and rot, and they excrete toxic substances, inhibiting the mycelium and causing the fruiting bodies to shrink and rot.

III. Prevention and Control Measures (1) Use standard mushroom houses or plastic greenhouses, and install screen netting. Coordinate temperature, humidity, light and air. (2) Keep the inside and outside of the mushroom house clean and hygienic; sterilize the compost at high temperature, sun-dry it and pile it for fermentation to kill insect eggs and larvae. (3) During the peak emergence period of adults, use mosquito repellent to repel and kill them, and use black light lamps to trap and kill them. (4) Chemical control. Spray fenvalerate.