Selection of Antagonistic Strains Against Watermelon Wilt and Their Biocontrol Efficiency

antagonistic Trichoderma spp. and 10 bacterial isolates against the pathogenic Fusarium oxysporum f. sp. niveum were isolated and selected from hundreds of soil and plant roots samples. Among the strains, Trichoderma viride TR 8 and Bacillus sp. B67 were the most effective ones and fermented to prepare their inocula and their mixture named Jiangenbao. Inoculation tests in greenhouse showed that all the biocontrol agents had good control effectiveness for control of watermelon wilt disease. Jiangenbao dust was more effective than its rwo constituents used alone. In field trials, when Jiangenbao dust diluted with soil at the ratio of 1∶50 was applied into seed delves before sowing, 80% control effect against watermelon wilt was obtained, which was apparently higher than that of carbendazim and amino oligosaccharin. Furthermore, it was also observed that Jiangenbao dust could enhance watermelon plant growth.