Study of antagonistic assessment of Trichoderma species on the causal agent of white stem rot of canola

In this research, effect of two species of mycoparasite including one isolate of Trichoderma virens, and three isolates of T. harzianum (T99,110,112) was studied against causal agent of canola (Sclerotinia sclerotiorum) in laboratory condition. Mycoparasitism mechanisms, growth rate of mycelia, power of colonization, and effect of volatiles and non-volatiles metabolites of these isolates were considered on S. sclerotiorum. Dual cultures studies were indicated that, these isolates have antibiosis and hyperparasitism activity. Among two species of Trichoderma, T. virens was better for purposes growth rate of mycelia and power of colonization than the other isolates like T. harzianum (T99, 110, 112). It was covered more than 50% of colony of S. sclerotiorum. T. harzianum (rn 120) decreased growth rate of mycelia of S. sclerotiorum 60-71.5% in cultural medium. In the test of volatile compounds, T. virens prevented mycelia growth of S. sclerotiorum on the basis of 40-55%. Also, it was prevented sclerotia germination, by means of intercellular secretories. Microscopic studies were indicated that, T. virens and T. harzianum can penetrate into mycelium of S. sclerotiorum by coiling and appressorium formation. For the first time, it was specified that T. harzianum rn120 from Gorgan field can destroyed sclerotia of S. sclerotiorum.