Study on the efficiency of Trichoderma isolates in controlling charcoal rot disease of soybean caused by Macrophomina phaseolina under greenhouse conditions

The charcoal rot disease caused by Macrophomina phaseolina is the most common disease of soybean in many parts of the world. Because of the soil-born and high saprophytic nature of the fungus in the soil, lack of effective control of the disease and environmental contamination due to the application of chemical pesticides, beneficial microorganisms such as Trichoderma species can be used for biocontrol of plant diseases. In this study, two isolates of Trichoderma harzianum and T. atroviride were studied in biocontrol of M. phaseolina and in the induction of plant resistance to pathogen under greenhouse conditions. The results showed that in treatments of soil inoculated with pathogen, T. harzianum isolate reduced the disease by 62 and 65 percent in sterile and non-sterile soil, respectively. The T. atroviride isolate reduced the disease by 59 and 62 percent in the sterile and non-sterile soil, respectively. The combination of two Trichoderma isolates reduced the disease by 67 and 70 percent, respectively. According to the results, in the treatment of soybeans inoculated with pathogen, T. harzianum isolate reduced the disease by 56 and 58 percent in sterilized and non-sterilized soil, respectively.The Trichoderma atroviride isolate reduced the disease by 52 and 53 percent in sterile and non-sterile soil, respectively. The combination of two Trichoderma isolates reduced the disease by 60 and 63 percent, respectively. Trichoderma isolates in the non-sterile soil were more effective in reducing disease. Trichoderma isolates in treatments of inoculated soil with the pathogen were more effective in reducing disease. T. harzianum isolate decreased the disease more than T. atroviride isolate in both methods that pathogen was used. The combining of two Trichoderma isolates also had a greater impact on the reduction of disease and resistance induction.