*Department of Life Sciences, Dibrugarh University, Dibrugarh, 786001, Assam, India. E-mail: pranabd1974@indiatimes.com
Department of Plant Pathology, Assam Agricultural University, Jorhat, 785013, Assam, India.
Sclerotinia rot caused by Sclerotinia sclerotiorum is a serious menace to the cultivation of french bean (Phaseolus vulgaris L.) in Assam. In vitro efficacy of antagonist by dual culture method was tested against S. sclerotiorum. Out of all the antagonists Pseudomonas fluorescens was found best causing growth reduction of 64.93 per cent followed by Bacillus snbtilis (62.86 %) and Trichoderma harzianum (59.08 %). Study on the mode of parasitism showed that the fungal antagonist initially caused coining and then lysed the pathogen hyphae and the bacterial antagonist ceased pathogen growth after coming in contact with the pathogen. Effect of fungal antagonist T. harzianum and bacterial antagonist's B. subtilis and P. fluorescens as seed treatment against sclerotinia rot was evaluated under field conditions. Seed treatment with T. harzianum was found has most effective in improving seed germination (18.43 %), reducing 90.46 % infection and increasing yield (69.51%) over control plot. Efficacy of B. subtilis and P. fluorescence as seed treatment against the disease was next to T. harzianum treatment respectively.
Antagonist, biological control, french bean, seed treatment, Sclerotinia rot
