What to Do When Shiitake Mushroom Logs Rot? Cause Analysis and Control Measures

Shiitake mushroom, also known as flower mushroom, monkey head mushroom, fragrant mushroom, fragrant trust, fragrant fungus, winter mushroom, fragrant mushroom, is the fruiting body of the plant Xiangxun of the Pleurotaceae family. Shiitake is the world's second largest [1] edible fungus, and is also one of our country's specialties, long known among the people as “mountain treasure”. It is a fungus that grows on wood. The taste is delicious, the aroma is refreshing, and it is rich in nutrients. Shiitake is rich in B vitamins, iron, potassium, and provitamin D (which converts to vitamin D after sun exposure); it is sweet in taste and neutral in nature. It mainly treats loss of appetite, shortness of breath, and fatigue.

Shiitake has long been known as the "king of mountain treasures", and is a high-protein, low-fat nutritional health food. Chinese physicians of past dynasties have all made famous discussions about shiitake. Modern medicine and nutrition science continue to study it in depth, and the medicinal value of shiitake is also constantly being discovered. Shiitake has a very high ergosterol content, which is effective in preventing and treating rickets; shiitake polysaccharides (β~1,3 glucan) can enhance cellular immunity, thereby inhibiting the growth of cancer cells; shiitake contains more than 40 enzymes from six major enzyme categories, which can correct enzyme deficiencies in the human body; the fatty acids contained in the fat of shiitake are beneficial for lowering blood lipids in the human body. Shiitake -- the queen of fungi. Shiitake, also called fragrant mushroom or winter mushroom, is a type of fungus that grows on wood. Because it tastes rather fragrant, has a pleasant aroma, and is rich in nutrients, it not only ranks above straw mushroom, oyster mushroom, and white button mushroom, but has long been honored as the “queen of fungi”.

Causes of shiitake mushroom log rot and control measures

Causes of shiitake mushroom log rot

Mushroom log rot mostly occurs in old mushroom-growing areas with many years of cultivation. Its root cause is invasion and infection by competitive contaminant fungi, so all factors that induce invasion and infection by contaminant fungi can cause mushroom log rot. Summarized, these include the following aspects.

1) Weakened stress resistance of cultivated varieties

Weakened stress resistance is a manifestation of variety degeneration, and this is the internal cause of mushroom log rot.

In old mushroom areas, some leading varieties have been planted for many years, their variety traits have degenerated, mycelial vitality has weakened, their adaptability to the environment is poor, and their ability to resist invasion by contaminant fungi has declined, so competitive contaminant fungi can take advantage of the opening and cause mushroom log rot. For example, the shiitake variety 241-4, because it has been cultivated for many years, has shown a clear decline in both yield and stress resistance in recent years, and its mushroom logs are also prone to rot.

2) Harsh cultivation environment

A harsh cultivation environment hinders mycelial growth, weakens stress resistance, or causes aging, death, and autolysis, thereby causing mushroom log rot. Factors such as high summer temperatures, poor ventilation, improper use of disinfectants, and deteriorated raw materials can also induce rot.

3) Damage from insect pests

Mushroom pests enter the mushroom log through ventilation holes to grow and reproduce, directly biting and feeding on the mycelium. After the mycelium is injured, a local environment of high temperature and high nutrients is formed, allowing competitive contaminant fungi to invade and infect, forming cross-infection between insects and fungi, and leading to mushroom log rot. In old mushroom areas, insect population density is high, damage is severe, and log rot is relatively more serious.

4) Damage from piercing holes

During cultivation, if the operation of piercing holes for ventilation is improper, the piercing tool (iron nail, bamboo skewer, etc.) directly injures the mycelium, leading to invasion and infection by contaminant fungi and resulting in rot.

5) Damage from pesticide injury

Shiitake mycelium or fruiting bodies are very sensitive to most pesticides and are prone to pesticide injury. For example, dichlorvos, dimethoate, and others have an obvious toxic effect on mycelium. When mushroom growers use these pesticides for pest control, the result, although it may seem effective, causes mushroom log rot.

Control measures for shiitake mushroom log rot

The control of mushroom log rot should focus on prevention, with treatment as a supplement, and should be carried through the entire cultivation management process.

1) Select excellent varieties, and purify and rejuvenate degenerated varieties.

2) Carry out cultivation management strictly according to the technical regulations for high-yield shiitake cultivation

① Arrange varieties reasonably. According to local climatic characteristics, select suitable varieties.

② Do a good job of sanitation in the cultivation site and environment. Waste mushroom logs from the previous year should be cleaned up in time; old mushroom yards should be sprayed with fungicides and insecticides to reduce sources of contaminant fungus contamination and lower insect population density.

③ Strictly control the amount of disinfectants used. The active ingredients contained in disinfectants currently on the market are all the same. The best dosage is 3-4 grams per cubic meter, and it must not exceed 6 grams.

④ Seal the inoculation opening with wax or tape to completely prevent insects and fungi from invading the mushroom log through the inoculation opening.

⑤ Piercing holes for ventilation must be operated according to standards. The diameter of the iron nail should be less than 2 mm, and the hole depth should be 1-1.5 cm. Pierce holes on sunny days, and do not pierce holes at tumor-like growths.

⑥ Carry out pest control and disease prevention reasonably. Choose the highly effective, side-effect-free, non-toxic, long-lasting mushroom-specific insecticide “Guchongjing”, spray once after the first hole piercing, then spray again after two months, and insect pests can be effectively controlled. Never use insecticides such as dichlorvos that are not suitable for use on shiitake.

3) Treat rotten logs in time

After discovering mushroom log rot, promptly pick out the rotten logs and stack them separately to avoid cross-infection among mushroom logs, and carry out the following treatment: ① Use a clean blade to cut off the rotten part, wipe the diseased spot, cut surface, and plastic film with a fungicide such as Kemeiling, then put the plastic film back and seal it tightly with tape to prevent water loss and reinvasion by insects and fungi. This operation is best completed under sterile conditions. ② For logs that begin to rot in the early stage of mycelial growth, resolutely carry out another round of mushroom log disinfection and inoculation (redo).