The Research About Trichoderma Spp. Against The Cucumber Fusarium Wilt And The Green Pepper Phytophthora Blight

The cucumber Fusarium wilt and the green pepper Phytophthora blight are the most common and harm serious two kinds of soil spreading fungal diseases in vegetable establishment planting. Effectively controlling them becomes the difficult problem solved eagerly in vegetable production.This research was on the basis of separation, screening antagonistic strains against Fusarium oxysporum and Phytophthora capsici. And carried on the identification to the two strains of Trichoderma spp. whose biocontrol effect is preferable. Then probed preliminarily into the antagonistic mechanism of biocontrol strains. And carried on the chitinase activity determination of the biocontrol strains. At the same time, we carried on the study about the effect of biocontrol by greenhouse pot experiment and the field plot experiment. It provided the theory basis and the technical support for the preparation of highly effective biocontrol agent and the biocontrol against vegetables fungal diseases.The main research content contains the following several aspects: 1st, 59 antagonistic strains were obtained by separating and purifying from soil samples which gathered from Shouguang and Cangshan in Shandong province. In these strains, 46 strains have antagonism against Fusarium oxysporum and 13 stains have antagonism against Phytophthora capsici.2nd, the antagonistic strains against Fusarium oxysporumand Phytophthora capsici were screened from 59 antagonistic strains and 25 strains which were provided by ACCC. By screening in room and greenhouse pot experiment, the effect of fungal strain NO.2 against the cucumber Fusarium wilt is best and the control effect was 54. 8%;the effect of fungal strain NO. 4 against the green pepper Phytophthora blight is best and the control effect was 67. 9%. The difference was remarkable. The two strains were both the strains of Trichoderma spp. which were provided by ACCC.3rd, the antagonistic mechanisms of the two biocontrol strains of Trichoderma spp. were probed into. The research indicated that the competition function and the parasitic function were mostly antagonistic mechanisms during the antagonism process of Trichoderma spp. against plant fungal diseases.4th, by adopting the direct-viewing and accurate method of reverting sugar, we carried on the chitinase activity determination of the biocontrol strains of Trichoderma spp. at different fermentation time. The result indicated that the change tendency of chitinase activity of the identical strain was approximately same at the different fermentation time. The chitinase activity of fungal strain NO. 4 rises highest after 145 hours. The chitinase activity of fungal strain NO.2 rises highest after 170 hours. The chitinase activity of fungal strain NO. 4 was higher than that of fungal strain NO. 2 at the same fermentation time.5th, on the basis of colony shape observation and morphology observation, and the Biolog physiology biochemistry examination and identification as well as ITS sequence analysis of fungal rDNA and so on, we identified two strains of fungal strain NO. 2 and fungal strain NO. 4 whose biocontrol effect were preferable. According to the test result, they were identified as Trichoderma longibrachiatum and Trichoderma citrinoviride. It provided new efficient antagonistic strains against the cucumber Fusarium wilt and green pepper Phytophthora blight.6th, we prepared solid biocontrol agent and carried on the field plot experiment about the effect of biocontrol agent controlling against the cucumber Fusarium wilt and the green pepper Phytophthora blight. The result indicated that the effect of biocontrol agent were 45.12% and 61.90% , respectively.Moreover the production increased 11. 06% and 37.19%, respectively. The effect of solid agent on the plant height of pepper was 8. 92%. The difference was remarkable.