Evaluation of efficacy of Trichoderma and Bacillus isolates in biological control of melon fusarium wilt

Three isolates of Trichoderma spp. (T. harzianum, T. longibrachiatum and T. viride) and two isolates of Bacillus bacteria were evaluated in biological control of Fusarium oxysporum f. sp. Meloni, the causal agent ofFusarium wilt disease of melon in the laboratory and greenhouse conditions. Dual culture, antimicrobial metabolites, and volatile metabolites were used in In vitro assay. Fungal pathogen colony area was recorded, compared with control and induced inhibition of growth was determined. A greenhouse experiments was also performed to test the efficacy of Trichoderma and Bacillus isolates in biological control of Fusarium oxysporum f. sp. melonis. This experiment displayed the antagonistic ability using dual culture simultaneous and dual culture non-simultaneous assays against fungal pathogen. Results showed that Trichoderma harzianum 6with 70% and T. viride10 with 52.9 reduction in the growth of fungal pathogen were the most efficient isolates respectively in comparison with the control. Results of dual culture assays also indicated that Bacillus 62 with 30.5%, in volatile metabolite test, Bacillus 15whit 12.37% and cell free culture test of Bacillus with 100%, were the most efficient in reducing mycelia growth of pathogenic fungus. Percent survival of the melon plants in pots treated with a mixture of both Bacillus, and Trichoderma isolates and healthy control was 100. However, the number of survived plants in other treatments varied from 65.2 to 79.38%. The above results were obtained statistically by mean comparison at 1% probability level using LSD test.