Biological Control of Soybean Charcoal Rot Caused by Macrophomina Phaseolina Using Trichoderma harzianum

Abstract

In this study, the antagonistic effect of Trichoderma harzianum T100 as a potential biocontrol agent against soybean charcoal rot caused by Macrophomina phaseolina were evaluated in in vitro and in vivo conditions. In dual culture tests, isolate T100 inhibited the mycelial growth of pathogen (55.3 %), then over ran and sporulated on the mycelia of M. phaseolina. Microscopic examination of mycelial interaction sites of T. harzianum and M. phaseolina showed that T100 penetrated mycelial cells of pathogen, moved inside and lysed them. Volatile test results indicated that the antagonist inhibited the mycelial growth of pathogen (12.2 %) and decreased the production of microsclerotia in culture media. Data from greenhouse experiments showed that, treatment of soil with T. harzianum T100 resulted in a high percentage of fresh and dry weights of root (57.5 % and 53.6 %) and aerial parts (22.9 % and 11.8 %) of soybean in sterile soil in compared with control. Additionally, reduction of microsclerotial formation on soybean root and steam, microsclerotial coverage, (62.5 %) showed the antagonist ability for initial inoculums reduction in later season