| The REMI mutant strain H6 of Trichoderma atroviride was studied as the original strain on the media formula and fermentation conditions of solid fermentation for the preparation of compost.And then, the technology of the maturity of straw compost was researched,on which were taken to check the growth promoting effect on vegetables. Moreover, it was studied on the biocontrol of Brassica napus sclerotinia stem rot and club root with T. atroviride. Those include its inhibitory mechanism and field efficacy to Sclerotinia sclerotiorum and P. brassicae spores.The results are as follows:1.The ingredients and radio of solid fermentation medium were as follows:corn residue:rice husk:straw powder:wheat bran=3:10:10:15.The fermentation condition was as follows:The optimum water content was 50%,optimal inoculum concen-tration was 20%,optimum fermentation temperature was 28℃,optimum fermentation period was 7 d.2.By making the straw compost, we found the treatments of adding 4000 mL water and setting the proportion among straw and decomposition maturing agent to 1:1,got a good maturity.Through the media formula selection of straw compost with different strains, we chose out the best treatment that were treated only by REMI mutant strain H6 of T. atroviride.Effective degradation of rice straw, the cellulase activity was significantly higher than other treatments, CMC activity was 3.48U. g-1,other treatment and control were not significant. FPA activity of each treatment compared with control had no signi-ficant difference in the level, and HTK3 processing's enzyme activity of FPA was the highes(1.13U.g-1). Straw manure treated by H6 has the highest reducing sugar content which was 17.14mg. g-1,whose difference was very significant compared with the control in the level of 29.6%; The N, P content in straw compost of all treatments were higher than those in control, while the potassium content was similar to the control. The highest nitrogen content was 1.88% both in H6 and HTK3 treatments; The phosphorus content of H6 treatment was significantly higher than other treatments for 5.9g. kg-1;The different-ce of all handlings of potassium was not significant. In the aspect of promoting health in the role of vegetable growing for tomato and cucumber, the plant height, fresh weight and dry weight of H6 treatment were all higher than the control.3.The REMI mutant strain H6 of T. atroviride has some potential of the biological control on S. sclerotiorum.In confrontation cultures, The area between T. atroviride H6 and S. sclerotiorum didn't form the transparent zone of inhibition, but formed a 6 mm brown significant inhibition zone after cultivating 96h. in the inhibition zone, the colony of S. sclerotiorum was malformed, whose growth was inhibited, the radius was significantly lower than the control's, and the inhibition rate of H6 on S.sclerotiorum's mycelial growth was 77.27%. T. atroviride H6 could continue to grow after contacting with S. sclerotiorum colonies, gradually completely covered colony of S.sclerotiorum, formed a very wide antagonistic band, and generated a large number of spores.T. atroviride H6 inhibited the formation of S. sclerotiorum, reduced the weight and quantity of sclerotia on S. sclerotiorum colony to the rate of 79.45% and 70.00%, respectively. It was observed under the microscope that T. atroviride H6 parasitized in S. sclerotiorum mycelium by a voluble or parallel way. The mycelial growth of S. sclerotiorum was restricted, malformed or distorted. The cytoplasmic was digested.T. atroviride H6's fermentation metabolites had inhibitory effect on mycelial growth of S. sclerotiorum.The highest inhibition rate reached 67.81% in the R1 treatment whose medium was mixed with the filter sterilization fermentation liquid and 2PDA at the volume of 1:1.The inhibition rate of the filter sterilization fermentation liquid treatment R was greater than autoclave liquid treanment R'.The inhibition rate of T. atroviride H6's fermentation metabolites on mycelial growth of S.sclerotiorum by using Method II was up to 61.36%,which was close to the result by using Method I. The inhibition rate of T. atroviride H6's fermentation volatile metabolites on the S. sclerotiorum only reached 17.5%,which was not as obvious as the fermentation metabolites'.T. atroviride H6's fermentation filtrate liquid has the inhibitory effect on germination of S. sclerotiorum.The germination percentages of S. sclerotiorum were 12%,70% and 80%, which were soaked with T. atroviride H6's fermentation filtrate liquid after cultivating 48h,72h and 96h.The S. sclerotiorum germinated slowly,and the growth of mycelium was inhibited by a certain degree. T. atroviride H6's fermentation filtrate liquid has the inhibitory effect on the ascospores germination of S. sclerotiorum.The inhibition rate of original filtrate on the ascospores germination of S. sclerotiorum was 59.34%. In control effect in vitro experiments, T. atroviride H6's spores suspension inhibited strongly the infection and expansion of S. sclerotiorum on the leaves.Its inhibition rate was 76.29%,then caused to produce a large number of H6 spores,whose lesion formation were smaller than control. T. atroviride H6's fermentation filtrate liquid and the diluted solution also could hibited significantly the S.sclerotiorum on the leaves and stems, and the highest inhibition rate reached 73.64% and 77.24%, respectively. In the experiment of field control effect, the relative efficacy of T. atroviride H6's fermentation metabolites was 76.28%, which were 80.41% of the relative control effect of carbendazim; The relative efficacy of T. atroviride H6's straw compost was 63.24%, which reached 66.67% of the relative control of carbendazim, indicating a great application development prospects.4.The REMI mutant strain H6 of T. atroviride has some potential for biological control on the P. brassica. T. atroviride H6's fermentative liquid has the obviously inhibitory effect on the germination of club root resting spores.The average correction inhibition rate of spore was 68.4%. From the view of field efficiency, the treatment dealing with T. atroviride H6's straw compost and fermentative liquid had low incidence, small disease index, and the average maximum control effect reached 61.4%.
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