Chiang Mai Journal of Science

     This study evaluated the efficacy of Trichoderma virens in controlling Agroathelia rolfsii, the causal agent of cowpea crown rot disease through in vitro, in vivo experiments. Following isolation and confirmation of the pathogen, dual plate assay was conducted in vitro. Pot and field trials were conducted under shade house and in both sterilized and non-sterilized field conditions. Agroathelia rolfsii was inoculated onto the crown area of cowpea seedlings using agar disc method, with one agar disc per plant. Trichoderma virens was applied as a spore suspension at planting and three-week intervals. Plant growth parameters, yield components, CFU, disease incidence were monitored throughout the study. According to the results, morphological, molecular identification confirmed the pathogen as A. rolfsii. Pathogenicity was verified through Koch’s postulate. In the dual plate assay, T. virens inhibited A. rolfsii by 86.02%. The application of T. virens significantly improved plant height, leaf number, flower number, pod number, root length, and seed weight, resulting in zero disease incidence. Furthermore, viability of T. virens in soil was ensured by showing fluctuations in CFU throughout the experimental period. In conclusion, T. virens exhibits significant potential as a biological alternative to chemical fungicides for controlling A. rolfsii, while enhancing cowpea growth.