Integrated Disease Management of Foliar Blight Disease of Onion: A Case Study of Application of Confounded Factorials

Abstract

Foliar blight is an important disease of onion, proving a major bottleneck in its production. Six pathogens were found associated with the disease, viz., Alternaria alternata, A. porri, A. tenuissima, Stemphylium vesicarium, Colletotrichum circinans and Cladosporium allii-cepae. Integrated disease management of the crop was attempted using chemicals (mancozeb at 0.25% and hexaconazole at 0.06%), bio-control agents, Trichoderma viride (Tv-1) and Trichoderma harzianum (Th-1), each at 1×10⁹ spores^-ml and phyto-extracts (Cannabis indica and Curcuma longa, each at 10%). Mancozeb at 0.25 per cent proved most effective in managing foliar blight of onion but was at par with hexaconazole at 0.06 per cent. Among bio-control agents used, application of T. harzianum (Th-1) resulted in lower disease intensity as compared to T. viride (Tv-1), though both were statistically at par with each other, but were significantly superior over the control. The phyto-extracts, C. indica and C. longa were ineffective in the disease management.