Evaluation of fungicides and bio-control agents in-vitro, against Sclerotinia sclerotiorum causes white stem rot disease in Rapeseed-mustard

Abstract

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (Lib.) de Bary is a major disease of rapeseed-mustard and it is considered next to Alternaria blight in causing yield losses as much  as 70 per cent in susceptible crop. The pathogen survives in the form of sclerotia on plant debris or in soil for more than 4 years, which makes it very difficult to manage with conventional approaches. Therefore, its management with fungicides and bio control agents remains an effective approach. The present study was undertaken in-vitro, using four fungicides viz., vitavax, propiconazole, mancozeb and azoxystrobin at three different concentrations i.e. 0.05%, 0.1% and 0.2% and three species of Trichoderma viz., T. harzianum, T. viride, T. koningii,to find out their relative efficacy in inhibiting mycelial growth of the pathogen. It is evident from the observations  that all four fungicides and three Trichoderma spp. resulted a significant effect on growth inhibition of S. sclerotiorum. Among all fungicides tested, vitavax and propiconazole were most effective at all three concentrations (0.05, 0.1 and 0.2 %) and inhibited cent percent radial growth of the pathogen, while mancozeb and azoxystrobin were least effective. Among the bio-control agents, T. viride was noted to be most effective antagonist followed by T. koningii resulting 78.50% and 72.21% growth inhibition, respectively. Whereas, T. harzianum showed minimum radial growth inhibition (49.25%) of S. sclerotiorum in this study.