Résumé
The purpose of this study was to evaluate the effectiveness of a commercial biofungicide such as Trichomix-HV in controlling damping-off disease in cucumber seedlings of greenhouses. In this regard, 504 fungal isolates were collected from greenhouses at 31 districts in city of Jiroft in Iran. Pythium aphanidermatum, P.ultimum, P. irregulare, Phytophthora drechsleri, and Ph. melonis accounted for 9.9%, 8.3%, 4.5%, 4.9%, and 21% of total isolates collected, respectively. Isolates of P. aphanidermatum obtained from commercial cucumber in greenhouses were tested in vitro and under greenhouse conditions for sensitivity to chemical and biological treatments. To this aim, Trichomix-HV a commercial formulation of Trichoderma harzianum strain T969 and the fungicides Metalaxyl and Metalaxyl MZ were amended into the culture medium as well as into sterilized or non-sterilized greenhouse soils inoculated by the pathogen and containing plants at the seedling stage. Trichomix-HV significantly [P < 0.001] reduced seedling infection at a rate of 82% when applied into soil medium at a concentration of 107 conidia ml/L and reduced vegetative growth of Pythium aphanidermatum in vitro. The result from this study shows that Trichomix-HV can be effectively used as a biocontrol agent for controlling damping-off cucumber seedlings and having the potential to replace chemical fungicides as a mean of disease control