Efficacy of Some Trichoderma Isolates as Biocontrol Agents Against Rhizoctonia solani Kühn in Bean (Phaseolus vulgaris L.)

This study was carried out to determine the in vitro and in vivo activities of Trichoderma isolates isolated from soil and plants collected from different provinces in 2020-2021 against Rhizoctonia solani, which causes root rot in beans. Using the pathogen as a trap, 61 Trichoderma isolates were obtained from 65 soil samples from 20 provinces. In addition, 8 Trichoderma isolates previously obtained from different plants were included in the experiment. Trichoderma isolates showed very strong (4 Trichoderma isolates), strong (1 Trichoderma isolate), moderate (18 Trichoderma isolates) and low level (18 Trichoderma isolates) hyperparasitic effects against R. solani in in vitro experiments with dual culture method. In comparison, some isolates (28 Trichoderma isolates) were found to be ineffective. As a result of in vivo tests with 10 Trichoderma isolates selected according to the effect results in vitro, it was determined that Trichoderma isolates were 8-89% effective against R. solani. The most effective Trichoderma isolates against R. solani was Trichoderma virens-130 with an 89% effect, followed by Trichoderma-106 and Trichoderma-162.1 with 82% and 75% effect, respectively. According to these results, it was observed that the isolates of Trichoderma, which were moderately and highly effective in vitro, significantly reduced the severity of the disease in vivo.