Studies on Seedborne Nature and Management of Alternaria alternate and A. brassicae in Pigeonpea

摘要

Pigeonpea [Cqjanus cajan (L.) Millspaugh] is one of the major grain legumes of the tropics and subtropics of the world, and is widely grown in many Indian states (Nene and Sheila, 1990). Most of the Alternaria spp. are primarily saprophytic; however,some species are true pathogens causing diseases of a wide range of crops (Bart Thomma, 2003). Leaf spot/blight of pigeonpea caused by Alternaria alternata Keissler has been observed occasionally in pigeonpea growing areas of eastern Indo-Gangetic plainsof Bihar and Uttar Pradesh, and also in Andhra Pradesh, Gujarat and Rajasthan (Mehta and Sinha, 1982). Infected plants produce discolored and wrinkled seeds that carry 31-35% infection of A. alternata (Khare et al., 2003). The seed-borne nature and seedtransmission of A. brassicae (Berk) Sacc. in rape seed and Mustard has been demonstrated (Shrestha et al., 2000), but no such report is available for pigeonpea. In the present investigation, the seedborne nature of Alternaria spp. was studied and new formulations with a combination of contact and systemic fungicides were evaluated against seedborne infection of Alternaria spp. affecting pigeonpea. This would greatly facilitate the long-term conservation and safe exchange of pigeonpea germplasm.