Studies On Identification And Controlling Of Trichoderma Spp.Isolated From Oyster Mushroom

Trichoderma spp. are the most important disease in oyster mushroom cultivation, they cause reduced yield and lower quality of the product. Trichoderma strains were isolated from substrates of edible mushrooms and were identified on the base of morphological characteristic and confirmed by molecular evidence. The optimum temperature of growth, pathogenicity analysis were investigated. We screened several oyster mushroom that resistant to Trichoderma from133Pleurotus stains and did some reseach in fruiting experiment in order to analysis their resistance. Influence of botanical pesticide and the botanicals extracts by ethanol to them were evaluated. The main results are:1、Thirty seven isolates were classified into4distinct species based on morphological and molecular identification, those four species included:Trichoderma harzianum、T. pleurotum、T. longibrachiatum、T. citrinoviride. T. pleurotum were the most important. According to the research, the morphologh and sequence analysis of rDNA-ITS have the same result and then phylogenetic tree of27strains were set up. The optimum temperature for mycelial growth was28～30℃. The results of virulence investigation showed that T. harzianum and T. pleurotum are stronger than others.2、We examined the competitive ability of Pleurotus spp. against two strains(T12and T33) of Trichoderma and gained18strains resistant to T12. In fruiting experiment, P131showed especially strong resistance to the pathogen, with the lowest yield losses and it’s well morphological characteristics. P131suits to crossbreed than other strains. Accroding to antagonistic reaction, genetic relationship between P131and other Pleurotus strains is farther.3、The results of toxicological test with pesticide showed that inhibition of five botanical pesticides to pathogen and mushroom was distinct. Mycelium of T12and T33in treatment were more weak than in control while mushroom hypha became better. The inbibitional effect of eugenol was the strongest to T. harzianum but worse to Pleurotus sp..4、The results of toxicological test in vitro with plant extract showed that ethanol extract of Syzygium aromaticum could completely control Trichoderma and Pleurotus. Theanol extract of Magnolia officinalis demonstrated mycelium inhibition rates of83.18%and spore germination inhibition rates of100%against T. Harzianum(T12) but totally stopped T. Pleurotum(T33). In general, ethanol extract of the two plants showed maximum efficacy against the two pathogen. Magnolia officinalis extract revealed mycelium inhibition rates of44.39%against oyster mushroom and made mushroom grew better.