Date Received: 29-05-2013 / Date Accepted: 15-08-2013
Rhizoctonia solani Kühnis a soil-borne fungus that causes root rot disease on a wide range solanaceous, cucurbitaceous and fabaceous plants such as tomato, soybean, cucumber, yard long bean and groundnut. Field surveys conducted during 2011-2012 in Hanoi showed that the damping-off disease occurred on all host plants in the Hanoi region. However, the disease incidences varied from crop to crop, ranging from 2.8% on tomato, 4.55% on groundnut, 7.6% on cucumber to 7.46% on yard long bean. The morphological, biological studies and particularly pathogenicity tests of five R. solani isolates from five above-mentioned diseased plants showed that all isolates were identical in morphological, biological and pathogenic features. Bio-tests of the R.solani isolates on artificial medium showed that the antagonistic fungus (Trichoderma viride) is effective in controllingl R. solani. In the dual culture test (Petri disks test), the inhibition efficacies of T. viride to two isolates of R. solani isolated from tomato and cucumber were 79.1% and 79.8%, respectively. Potting test, in which plants were grown in sterilized soil in the greenhouse showed that the control efficacies of T. viride to these two R. solani isolates were 73.2% on tomato and 76.2% on cucumber..
