Detailed Explanation of the Principles and Measures for Edible Mushroom Disease Control

The control of diseases and pests in edible mushrooms is more difficult than in other crops. On one hand, the environmental conditions required for the growth and development of edible mushrooms - a nutrient-rich culture substrate, a relatively enclosed space, suitable temperature, and dark, damp conditions - are also highly suitable for the occurrence and development of pests and diseases. Moreover, pests and contaminant organisms often occur within the culture substrate, mixed together with the mycelium of the edible mushrooms, making it difficult to separate them and take effective control measures independently. On the other hand, the edible portion of edible mushrooms - the fruiting body - is completely exposed, lacking other protective tissues, and is a health food. The mushroom body has strong water absorption capacity, so once inappropriate pesticide control is applied during the fruiting period, it will cause pesticide residues. Therefore, adopting scientific and reasonable disease and pest control methods is an important guarantee for achieving high yield, high efficiency, high quality, and pollution-free edible mushroom production.

1: Principles for the Control of Non-infectious Diseases

The key to non-infectious diseases lies in prevention. From the preparation of the culture material and the adjustment of the mycelium-running conditions to the control of the mushroom house environmental conditions, throughout the entire development process of edible mushrooms, every possible effort should be made to create conditions favorable for the growth and development of edible mushrooms to suppress the occurrence of such diseases.

2: Principles for the Control of Infectious Diseases

① Control principles: The occurrence and spread of infectious diseases require four conditions, namely the pathogen, the host, suitable environmental conditions for infection, and re-infection and spread. Blocking the pathogen: prevent the infection source from entering the mushroom house, such as not using diseased spawn or culture material, conducting standardized secondary fermentation or sterilization, steam-sterilizing or chemically disinfecting casing soil materials before use, thoroughly disinfecting old mushroom houses, and cleaning the environment. Blocking transmission routes: For any disease, if only one infection occurs during the growing period, it generally will not cause harm; only when re-infection occurs will it cause significant harm to production. Therefore, blocking transmission routes after disease occurrence is very important, such as disinfecting tools and promptly eliminating insects and mites. Blocking the growth of pathogenic bacteria: Most diseases favor high temperature and high humidity; appropriately lowering temperature and humidity and strengthening ventilation have varying degrees of inhibitory effects on various pathogenic microorganisms. Killing pathogens: Conduct thorough disinfection of the environment inside and outside the mushroom house and apply necessary chemical control.

② Control principles: Once an infectious disease occurs on the fruiting body, the entire fruiting body completely loses its commercial value. Due to the high temperature and high humidity environment of the mushroom house and the daily necessary watering management, the speed of disease transmission and spread is greatly faster than the growth speed of the mushroom body.

Disease prevention should follow these points:

Focus on the treatment of culture material and casing soil: The pathogens of many edible mushroom diseases naturally exist in the culture material and casing soil materials, and are also the initial infection sources of edible mushroom diseases. Therefore, in addition to the necessary fermented material cultivation, especially in disease-affected areas or old mushroom sheds, cooked material cultivation should be used as much as possible. In the practice of oyster mushroom cultivation, yellow blotch disease has been widespread in recent years and shows a trend of serious development, but cooked material cultivation has basically not caused significant harm.

The disinfection of the cultivation site and mushroom house environment should be done well: Many pathogenic bacteria naturally exist on soil surfaces, in the air, and on various organisms, especially on the walls and bed frames of old mushroom houses, which retain pathogenic bacteria from the previous production season. The simplest and most economical method for disinfecting the cultivation environment and site is exposure to sunlight. The mushroom shed roof covering can be lifted, first exposing the ground to sunlight, then deep plowing, and then exposing to sunlight again. Disinfectant solution, peracetic acid, bleaching powder, and sulfur are all good environmental disinfectants and are pollution-free.

Cultivation control should be maintained throughout: Throughout the entire cultivation process, special attention should be paid to the control of temperature and humidity, strengthening ventilation to suppress the growth and infection of pathogenic bacteria, while also paying attention to tool disinfection and creating a clean growing environment.

Once disease occurs, chemical treatment should be carried out as early as possible: Once disease occurs during the fruiting period, it should be treated as early as possible, such as removing diseased mushrooms, treating the disease foci, and spraying fungicides. If treatment is not timely, it can easily cause disease epidemics and spread that are difficult to control.

Harvest mushrooms first, then apply chemicals; leave sufficient residue period after fruiting: When conducting chemical control, if mushrooms are not harvested first, the chemicals can easily contaminate the mushroom bodies and cause large amounts of residues. Therefore, when applying chemical control, mushrooms must be harvested first, then chemicals applied. After application, the mushroom house should adopt drier management to suppress the formation of fruiting body primordia. The residue period of currently used fungicides is generally 10-14 days, while most edible mushroom fruiting bodies require about 7 days from primordium formation to maturity. Therefore, after application, it is best to wait 6-8 days before allowing fruiting.

3: Principles and Control Measures for Contaminant Organisms

The relationship between contaminant organisms and edible mushrooms is equivalent to the relationship between weeds and crops. They do not directly attack edible mushrooms like pathogenic bacteria, but rather compete with edible mushrooms for nutrients through growth on the substrate, while also producing toxins to inhibit the growth of edible mushrooms. Therefore, we often call them competitive contaminant organisms. The contaminant organisms harmful to edible mushrooms are mainly molds, a few higher fungi, bacteria, and slime molds.

Contaminant organism control in cooked material cultivation: The main sources of contaminant organism contamination in cooked material cultivation include contaminated culture material (incomplete sterilization), contaminated spawn, contaminated inoculation tools, invasion of external contaminant organisms during inoculation operations, and invasion of external contaminant organisms during the cultivation period. Therefore, the key points of control are strict aseptic operations during inoculation, not transferring primary spawn too many times, and timely use of spawn after it has fully colonized the spawn bags (bottles) to prevent excessive aging of the spawn.

Contaminant organism control in raw material and fermented material cultivation: Various microorganisms naturally exist in raw materials and fermented materials. During the cultivation of edible mushrooms, whether contaminant organism contamination occurs mainly depends on the balance among various microorganisms in the microbial flora of the material. Once this balance is broken, contamination occurs. The following measures should generally be taken for prevention:

① Increase the pH value of the culture material to inhibit the growth of molds without significantly affecting the growth of edible mushroom mycelium.

② The culture material should be appropriately drier and have increased permeability to promote the growth of edible mushroom mycelium and inhibit mold growth.

Appropriately increase the inoculation amount to occupy the population advantage among microorganisms in the material.

③ Appropriately add fermentation agents and other microbial preparations or fungicides such as Shierkang and Kemeiling to the material, which can inhibit mold growth.

④ Create environmental conditions favorable for the growth of edible mushrooms, such as temperature and ventilation, to promote the growth of edible mushroom mycelium and suppress the reproduction of contaminant organisms.

⑤ Scientifically and reasonably ferment to create a selective substrate that only favors the growth of edible mushrooms and not the growth of contaminant organisms, including physical and chemical properties and microbial flora suitable for the growth of edible mushrooms.

Contaminant organism contamination control during the fruiting period: Generally speaking, initial contaminant organism infection is not likely to occur during the fruiting period unless environmental conditions are excessively unsuitable, such as high temperature and high humidity or excessive uncleanliness. Effective ways to prevent contaminant organism contamination during the fruiting period: First, prevent high temperature and high humidity and ensure sufficient ventilation; second, promptly clean the bed surface and clean the mushroom house to maintain good sanitary conditions.