Green mold disease caused by Trichoderma species has recently caused considerable damage to oyster mushroomindustries in Korea. This disease Trichoderma, Penicillium, Aspergillus, such as in (genus) to be included in a disease caused by aspecies that collectively the largest incidence and damage is caused by the pathogen Trichoderma genus. T. longibrachiatum,Trichoderma koningii, Trichoderma virens, T. hazianum, T. atroviride, and T. pseudokoningii were detected on oyster mushroombeds and, of them, T. virens, T. hazianum, T. longibrachiatum was the most frequently detected. The knowledge concerningphysiological and ecological properties of Trichoderma spp. was essential for their effective control. T. longibrachiatum hyphalgrowth is very fast, spore formation, and, particularly well-chlamydospore formation characteristics, and reviews are dark greendiscoloration. T. koningii, fast mycelial growth, aerial hyphae and spores in aerial hyphae formation is concentrated. T. virens,especially if the color change caused by spore-forming, slow, late in infection, the more severe the damage is discovered. T.hazianum fast mycelial growth, white aerial hyphae and late turns dark green. After spore formation hyphae glob of whitepustules or tufts on the top of the formation. T. atroviride. aerial hyphae usually the mycelial growth and spore formation in theunlikely event of the formation and smells similar to the smell of coconut is that. Fast T. pseudokoningii mycelial growth, sporeformation is formed around the inoculation site, discoloration of the medium color and well formed chlamydospores.