Potential of Botanicals and Biocontrol Agents against Rhizoctonia solani Kühn Incitant of Web Blight Disease of Mung Bean: An invitro Evaluation

Abstract

The antagonistic activity of biocontrol agents and botanicals was evaluated against Rhizoctonia solani Kühn which is reputed as one of the destructive plant pathogens and a ubiquitous soil fungus. The pathogen causes huge losses in the production of mungbean in India. For this study, disease infected leaf samples were collected from pulse pathology block situated at Normon E. Borlaug Crop Research Centre, Pantnagar based on cultural, morphological and disease potential studies and then evaluated the pathogen against five botanicals viz. Calotropis, Ocimum, Aloevera, Neem and Bael at 5, 15, 25 and 35 per cent concentration through poison food technique and two bioagents viz. Trichoderma harzianum (Th-14) and Pseudomonas fluorescens (Psf 173) by dual culture technique in the laboratory of the Department of Plant Pathology, College of Agriculture, GBPUA&T, Pantnagar in 2017. Observations were taken after the full growth of the control in case of botanicals and after 24, 48 and 72 hours in case of biocontrol agents for the assessment of the inhibitory effects.In the presence of botanicals the variability in the growth inhibition over control was observed, as the maximum growth inhibition was observed in Calotropis @ 5, 15, 25 and 35 % concentration (71, 81, 84 and 86 %) and least in Aloevera (4.81, 10.56, 29.07 and 37.59 %) respectively, likewise in the presence of bioagents maximum growth inhibition was observed in Trichoderma harzianum (Th-14) (61.29 %) and least in Pseudomonas fluorescens (Psf 173) (39.53%) respectively. It was observed that all the botanical extracts and biocontrol agents resulted in significant reduction in the mycelial growth of Rhizoctonia solani in vitro.