EFFICACY OF Trichodarma harzianum TO CONTROL Sclerotium rolfsii CAUSING DAMPING-OFF AND FOOT ROT OF VEGETABLES

Abstract

Experiments were conducted in the Plant Pathology laboratory, HSTU to find out the effectiveness of local isolate of Trichoderma to control Sclerotium rolfsii causing damping-off and foot rot of some selected vegetable crops during the period of June-April 2014/15. Soil samples were collected from rhizosphere zone of different vegetable crops at different locations of Dinajpur district. Trichoderma isolated from the rhizosphere soil of Indian spinach was identified as Trichoderma harzianum. Another isolate of T. harzianum was purified from the commercially formulated product by Rural Development Academy (RDA), Bogra. Sclerotium rolfsii was isolated and purified from infected eggplant. The two isolates of T. harzianum were tested for their antagonistic activity against S. rolfsii following the dual culture method on petridish. It was found that local isolate of T. harzianum showed better inhibition (92%) than RDA isolate (85%). The local isolate of T. harzianum was formulated with blackgram based substrate to test its efficacy as soil treatment. In pot experiments, three treatments viz. T1 (formulated Trichoderma @ 10 g/kg soil), T2 (formulated Trichoderma @ 15 g/kg soil) and T3 (formulated Trichoderma @ 20 g/kg soil) along with a sterilized soil as control were tested against S. rolfsii causing the damping off and foot rot of bean, eggplant, tomato, cabbage and Indian spinach. Among the treatments, soil application with T3 (formulated Trichoderma @ 20 g/kg soil) showed the highest effect followed by T2 and T1 in controlling pre-emergence death, damping-off and foot rot (71.87-100%) increasing germination percentage (34.37-48.46%) in all the crops over control. Seed treatment with spore suspension of Trichoderma @ 5.02 × 106 CFU/ml was also found effective against different seed-borne pathogens resulting higher germination (23.26-49.62%) and less incidence of foot rot and damping-off of seedlings (140.0-322.33%) over control. Finally it may be concluded that formulated Trichoderma as soil treatment (@ 20 g/kg soil) and spore suspension as seed treatment (@ 5.02 × 106 CFU/ml) resulted statistically significant in controlling the S. rolfsii causing damping-off and foot rot diseases of vegetable with higher germination.