Control Efficacy Of Several Fungicides Against Trichoderma And Its Effect On Mushroom Growth

Trichoderma harzianum is the main pathogen in edible mushroom cultivation, it causes severe crop losses and quality decrease. To evaluate the control effect of natamycin on Trichoderma harzianum and its safety on oyster mushroom cultivation, natamycin which is used in the food industry with 6 common agricultural fungicides is supplied as test fungicides by the method of mycelia growth inhibition and oyster mushroom cultivation experiment, the aim is to screen out the best mixture ratio of natamycin with these fungicides. In addition, the antagonistic ability of 58 strains which were selected from Pleurotus ostreatus, Auricularia auricula, Ganoderma Lucidum Karst, Volvariella volvacea and Lentinus edodes in the hope of providing reference basis to Trichoderma harzianum disease control. The main research results are as follows:1. The result of fungicides toxicity determination showed that the control effect on Trichoderma harzianum from high to low was as difenoconazole, carbendazim, chlorothalonil, natamycin, bromothalonil and iprodione, with the EC50 value of 0.45,0.71, 1.39,1.55,8.65,12.45 and 18.19mg/L respectively, it was clear that natamycin has a good control effect on Trichoderma harzianum.2. The fungicides combinations were designed by means of Horsfall, natamycin was mixed with 6 fungicides respectively. The mixture results showed that the combination of natamycin mixing with difenoconazole, carbendazim or chlorothalonil had better synergism effect on Trichoderma harzianum, hence these mixtures were suitable for fungicides combination, while the control effect was not good when natamycin was mixed with bromothalonil, azoxystrobin or iprodione relatively.3. By summarizing up the results of mycelial growth experiment and oyster mushroom cultivation experiment, it was clear that natamycin and carbendazim had very little inhibition effect on myceliam growth, the inhibition effect of treatment group which mixed with natamycin and carbendazim was 12.69% and 19.79% respectively at high concentration, they also had little effect on mushroom production, the production was 85.11% and 86.29% to that of control respectively. Compared with chlorothalonil and difenoconazole, natamycin and carbendazim were safe on mycelial growth; compared with bromothalonil, azoxystrobin or iprodione, they had higher control effect on Trichoderma harzianum, and were also safe on mushroom growth.4.58 strains which commonly were used on the production selected from Pleurotus ostreatus, Auricularia auricula, Ganoderma Lucidum Karst, Volvariella volvacea and Lentinus edodes, were carried out in antagonistic experiment, and 17 resistrant strains were screened out from these strains,6 strains had the best resistance to Trichoderma harzianum among them.