Abstract

Leaf blight caused by Rhizoctonia solani is one of the most serious diseases that cause damage to turmeric crop. Fifty percent disease incidence was observed in turmeric growing areas of Andhiyur (Erode district) and Mettur (Salem district) of Tamil Nadu, India. The antifungal efficacy of botanicals, bioagents and fungicides were tested against R. solani in vitro. It was observed that seed extract and oil cake of Madhuca longifolia suppressed the mycelia growth (34.81; 49.63%), sclerotial formation (100%) and production of biomass (2.18; 2.41 mg) of R. solani followed by leaf extracts of Azadirachta indica and Littorina littorea. Among the bioagents native isolate of BSoya1 of Bacillus spp., Cg1 of Chaetomium spp., Pf1 of Pseudomonas spp. and Tv1 of Trichoderma spp. shown more than 50% antagonistic effect on mycelia growth and 100% on sclerotial formation. The complete fungal growth inhibition was observed in Nativo and Bavistin fungicides amended medium. Then, the basal soil application of mahua cake and T. viride in the ratio of 1:2 (1 g of mahua cake mixed with 2 g T. viride per kg of pot soil) followed by foliar spray of Nativo @ 0.5% significantly mitigated the leaf blight (8.6%) over the inoculated control (50.51%) in pot culture experiments.

Key words: Turmeric, efficacy, fungicides, bioagents, botanicals, Rhizoctonia solani.