New foliar diseases of potatoes due to rhizoctonia and chaetomium spp

Abstract

Rhizoctonia solani (Thahatephorus cucumeris) was observed inciting irregular lesions of unlimited size on leaves and causing symptoms of foliage blight. Chaetomium cochlioides, C. globosum and C. funicola were found associated with grey to light brown spots or patches developing towards leaf margin or interveinal spaces. The isolates of R. solani were highly virulent while the isolates of all the 3 Chaetomium spp. were less virulent. Among different cultivars tested against Rhizoctonia blight, however, varieties Craigs Defiance, Kufri Khasigaro, Kufri Naveen and VB-8 were less susceptible than Kufri Alankar, Kufri Chandramukhi, Kufri Jeevan, Kufri Jyoti and Kufri Shakti.