Control Methods for Green Mold Disease in Ganoderma lucidum Cultivation

Green mold (Trichoderma viride Pers. ex Fr.) belongs to the subphylum Deuteromycotina, class Hyphomycetes, order Moniliales, family Moniliaceae, genus Trichoderma.

1. Morphological characteristics: The hyphae are slender, colorless, septate, and much branched. Conidiophores arise from lateral branches of the hyphae, opposite or alternate, generally with 2-3 branchings, bearing flask-shaped or conical phialides that produce conidia. The conidia are mostly spherical, with the spore wall bearing small warty protuberances, green or blue-green. On PDA medium, the colony is initially white and cottony, later becoming dark green. 2. Disease development pattern (1) Transmission route: Conidia are spread by airflow, water, insects, and so on. Old mushroom houses, contaminated tools, and raw materials are the main sources of primary infection. The conidia produced after infection can cause repeated re-infection many times. (2) Conditions for occurrence: It is widely distributed in soil, air, and various organic matter in nature. Any substrate that is not thoroughly sterilized or poorly composted and fermented is very easily infected. At temperatures of 15-30°C, the spore germination capacity of green mold is highest; the hyphae can grow within the range of 4-42°C, with the fastest growth at 25-30°C; a high-temperature environment is favorable for spore germination and hyphal growth; it prefers a slightly acidic environment, but it does not die even when the pH rises above 7. 3. Damage symptoms: During both spawn expansion and cultivation, it can be infected and damaged by Trichoderma. Green mold has a very strong adaptability to the environment, and the cellulase, cellobiase, and other enzymes it contains are highly active. On substrates rich in lignin and cellulose, it develops extremely easily, and once it infects, it grows and spreads very quickly, turning the entire substrate layer green, and it secretes toxins that destroy the host's hyphae and cytoplasm, causing the host to die quickly. It can be called a devastating, catastrophic disease and contaminant. 4. Control methods (1) Focus on prevention, do a good job of cleaning and sanitation in the production site, and the ingredients must be fresh, fully dry, correctly proportioned, and thoroughly sterilized. (2) When contamination is found during spawn production, it should be discarded and redone; when cultivation bags are contaminated, in mild cases the diseased area can be dug out and lime powder or fungicide applied locally, while in severe cases it should be burned; when log cultivation is locally contaminated, use a sharp knife to shave off the bark and wood of the affected part and apply or sprinkle fungicide, and if the contamination is severe and widely distributed, it should be gathered and burned. (3) When mixing the substrate, add 0.1% of 70% thiophanate-methyl, and after high-pressure sterilization, a relatively good control effect can be achieved.