Fertilization Methods for Edible Fungi and Non-Polluting Prevention and Control Measures for Contaminant Fungi

The relationship between contaminant fungi and edible fungi is comparable to that between weeds and green crops. They do not directly attack edible fungi like pathogenic fungi do; instead, by growing on the culture substrate, they compete with edible fungi for nutrients and simultaneously produce toxins that inhibit the growth of edible fungi. The main contaminant fungi harmful to edible fungi are molds and a small number of higher fungi, bacteria and slime molds.

1. Contaminant fungus control in sterilized substrate cultivation. The main sources of contaminant fungus contamination in sterilized substrate cultivation include: the substrate carrying fungi (incomplete sterilization), the spawn carrying fungi, inoculation tools carrying fungi (incomplete sterilization), invasion of external contaminant fungi during inoculation operations, and invasion of external contaminant fungi during the incubation period. Accordingly, the key points of prevention and control should be: ① Select clean, fresh raw materials free of mold, and sterilize them thoroughly. This is the first line of defense against contaminant fungus contamination. ② Carefully select spawn to eliminate spawn carrying contaminant fungi. ③ Formulate the substrate scientifically, controlling moisture and pH value, to create substrate conditions unfavorable to contaminant fungus infection. Experience shows that when there is a lot of wheat bran in the substrate or after sugar is added, the mold contamination rate is relatively high. When soybean powder or cake fertilizer powder is used to replace part of the wheat bran and no sugar is added, the mold contamination rate can be significantly reduced. When the moisture content is relatively high, mold contamination occurs more; when the moisture content is relatively low, mold contamination occurs less. ④ Inoculate strictly, and strictly control the operational steps. ⑤ Create suitable incubation conditions, with particular attention to a clean and dry site, to reduce infection by external contaminant fungi.

2. Contaminant fungus control in raw substrate and fermented substrate cultivation. Various microorganisms naturally exist in raw substrate and fermented substrate. During the incubation period of edible fungi, whether contamination occurs mainly depends on the state of balance among the various microorganisms in the substrate's microflora; once this balance is broken, contamination will occur. The following measures are usually taken to prevent contamination. ① Increase the pH value of the substrate to inhibit mold growth without significantly affecting the growth of edible fungus mycelium. ② Keep it appropriately on the dry side and increase air permeability to promote the growth of edible fungus mycelium and inhibit mold growth. ③ Increase the inoculation amount to gain dominance in the microbial population of the substrate. ④ Add an appropriate amount of fungicides such as carbendazim to the substrate to inhibit mold growth. ⑤ Create environmental conditions favorable to the growth of edible fungi, such as temperature and ventilation, to promote the growth of edible fungi and thereby inhibit the reproduction of contaminant fungi. ⑥ Carry out scientific and reasonable fermentation to produce a selective substrate that is only favorable to the growth of edible fungi and unfavorable to the growth of contaminant fungi, including physicochemical properties and microflora suitable for the growth of edible fungi.

3. Contaminant fungus control during the fruiting period. Generally speaking, initial contaminant fungus 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. The effective ways to prevent contaminant fungus contamination during the fruiting period are, first, to prevent high temperature and high humidity and ensure sufficient ventilation, and second, to promptly clean the bed surface and clean the mushroom house to maintain good sanitary conditions.