Creation And Application Of Trichodema Bio-Seed Coating Agent

Maize soil-borne disease is one of major diseases that threaten the corn production. By now, seed dressing with the chemical pesticides has become widely-used measure against soil-borne diseases. However, the problems in the application of chemical pesticides are concerned seriously such as overdosage or long time use of chemical pesticide has significantly impacted ecological environment,in this case searching new control measures friendly to environment has become great challenges to scientists in agriculture . Trichoderma, a inhabitant living widely in the soil, has already been considered as one of most effective bio-control fungus in the world. It enable not only to prevent a rank of crop plant diseases, but also promote growth and increase yield. Therefore, it is significant to develop Tricoderma biocontrol agent against maize soil-borne disease. In our study, we screened Trichoderma strains with high antagonistic activity, and then optimized fermentation conditions of sigle factor or multiple factors through orthogonal design.And also Trichoderma biomass produced under the optimal condition was prepared into seed soaking agent, seed coating agent or powder used to treat soil. Eventually all biocontrol agents were outreached all over the country.Two strains (SG3403,SH2303) , which were screened from 48 wild strains of Tricoderma collected from farmland soil in east China, showed a strong antagonistic activity against Fusarium moniliforme,Fusarium graminearum, Rhizoctonia solani. The fermentation condition for Tricoderma LYI1208 was optimized through single factor test and orthogonal test. Optimized fermentation condition achieved in flask was also applicable to 300L fermentation tank. Yield of chlamydospore could reach 107 /mL on the fifth day under optimized fermentation condition. Soaking seed in 50 fold-diluted fermentation solution for 6 hours offered greatest growth promotion and disease-prevention. One selecetd coating materials was demonstrated to be best for seedling growth. Streptomycin added into fermentation broth was effective to inhibit bacterial pollution without any negative impacts on maize grow. Tricoderma biomass powder was obtained through a secondary fermentation and then mixed with 9 kinds of pesticides in different combinations, in which two Trichoderma strains and their combinations with avermectin,shenqinmycin, validamycin-Bacillus cereus showed their most significant synergistic promotion to seed germination and seedling growth if ratio of both components are favorable in complex formulation, which consequently could be used as valuable candidates for innovating new complex seed coating agents .The bio-seed coating agents composed of Trichoderma strain was able to induce maize defense response in leaves to Currularia leaf spot infection in pot experiment, POD and PAL enzymes were significantly increased in seedling leaves grown from seeds treated with Trichodema strains ,the control efficiency could reach 50%-70% either in pot or field experiment .Field experiment and demonstration with 17 Trichoderma seed-coating agents and soaking agents were arranged in 20 experiment stations over 13 provinces covering farming land of more than 247.11 acre, the significant improvement in diseases control and yield increase were achieved in most field experiments .