biological control of the wheat root rot caused by fusarium graminearum by using fungal antagonists in mazandaran province

fusarium root and foot rot of wheat is caused by the fungus gibberella zeae (fusarium graminearum). this disease causes significant yield loss under infested soil and favourable condition. the aim of this study was to evaluate the efficacy of selected fungus strains against the wheat soil-borne pathogen f. graminearum under greenhouse and field conditions. the most potent isolates were 3 isolates (all of isolates were identified as trichiderma harzianum) out of 15 isolates, which have numbers 2, 10 and 12. these isolates were selected for the following experiments. mycelial growth of f. graminearum (f3) was reduced by cell free and volatile metabolites of trichoderma harzianum strains. t. harzianum strains 12 significantly (p*0.5) reduced the incidence (8.3%) and severity (4.1%) of disease, 35 days after inoculation and increased the 1000 grain weight (38 g) in greenhouse conditions. for confirmation of the greenhouse tests, the selected antagonists were reexamined in field trials. this strain could also reduce the disease incidence (10%) and severity (3.1%).