Study On Synergism Of Trichoderma Harzianum Combined With Five Fungicides To Botrytis Cinerea And Synergistic Mechanism

Chemicals and biological agents are important parts of plant diseases controlling.With biological agents entering the market and gradually being used in the production, theera has been arrival of coexistence of chemical and biological controlling in plant diseasescontrolling. In the process of common acting to the plant pathogens of biological agentsand chemicals, the complex relationship of mutually inhibited or reinforcing maybe occur.Rational choice and conbine used of biological agents and chemical may be make up theinsufficient for each other, and even appear synergies. This can improve the controllingeffect of biological agents, simultaneously can reduce the usage amount of chemicalpesticides, which is worths to study in plant disease controlling. As one of biologicalagents，Trichoderma has been made into a number of commercial preparations using inplant disease controlling. While the Trichoderma had the problems of instability effect,easily affected by environments, thus it is still can not completely replace the action ofchemicals in production. In this paper, synergism of Trichoderma harzianum combinedwith five fungicides to Botrytis cinerea and synergistic mechanism were studied, and firstdiscussed the synergism evaluation methods of chemical pesticide conbine used fungalbiocontrol agents which can be cultured. The main results are as follows:1.The inhibitory effect of Trichoderma harzianum to Botrytis cinerea wascomprehensive determined, the results showed that T.harzianum has strong inhibitoryeffect to B. cinerea.2.The toxicity effect of ten kinds of fungicides with different mechanism toT.harzianum and B. cinerea were tested by mycelium growth rate method, and establishedthat the ratio of toxicity (EC₅₀) more than one can be used as the standard of screenedfungicide of combined with T.harzianum, and screened out the test agents were boscalid,fluazinam, azoxystrobin, fludioxonil and SYP-Z048.3.The inhibitory effects of T.harzianum combined with boscalid, azoxystrobin,fludioxonil, fluazinam and SYP-Z048to B.cinerea were all enhanced determined byconfrontation method, mycelium growth rate method and in vitro leaf, which suggestedthat T.harzianum had synergism with the five fungicides, and the inhibitory rate enhancedmore significantly while the fungicide inhibition T.harzianum was zero or very small combined with T.harzianum to B.cinerea.4. The results of evaluation synergism of fungal biocontrol agents and chemicalpesticides showed that:the method of evaluation synergism between chemical pesticideswas unsuitable using in evaluation synergism of chemical pesticides conbined with fungalbiocontrol agents which can be cultured, and put forward a feasible method of evaluationsynergism of fungal biocontrol agents and chemical pesticides, namely synergy coefficientmethod.5.The preliminary synergism mechanism of T.harzianum combined with boscalid toB.cinerea was determined by microscopy method, mycelium growth rate and disc filtermethod, the results showed that the synergism mechanism was boscalid result in themycelium partial dissolution of B.cinerea, its beneficial to T.harzianum occupy nutritionand space, and enhanced the antifungal activity of volatile compounds of T.harzianum toB.cinerea; the nonvolatile matter and crude enzyme solution of T. harzianum after combineused of T. harzianum and boscalid to B. cinerea was no significant enhanced.