Integrated Disease Management of Collar Rot of Lentil (Lens Culineris) Caused by Sclerotium Rolfsii Sacc

Abstract

Lentil is an important pulse crop. It contributes about 8-9% of the total pulse production in India. More than 90% of the lentil area is covered by Madhya Pradesh and Uttar Pradesh states which contribute more than 70% of country's lentil production. It is a major source of protein, minerals and vitamins. However, lentil yield potential is far below than other legume crops. The low yield of lentil is associated with poor management practices, unavailability of quality seeds and specially lack of proper disease management. Diseases play an important role in yield reduction. The Lentil crop is infected by many pathogens (fungi, bacteria, viruses and nematodes) some of them are collar rot (Sclerotium rolfsil) , anthracnose ( Colletotrichum lindemuthianum ), ascochyta blight (Ascochyta fabae f.sp. /entis ), botrytis gray mold (Botrytris cinerea), fusarium wilt (Fusarium oxysporum f.sp. lentis), and rust (Uromyces jabae). Collar rot of lentil is an important seedling disease pa:rticularly under high moisture and high temperature conditions. This disease is caused by Sclerotium rolfsii Sacc. The disease is also widely prevalent in Utter Pradesh and causing 25 to 35% yield loss. Infected young seedlings show damping-off symptoms. When plants are infected at an advanced stage they gradually tum pale, droop and dry. Three inoculation techniques viz. Agar Disc, Wheat grain inoculum and Tooth Pick methods were applied for artificial inoculation of S. rolfsii Sacc. in lentil plants. Wheat grain inoculum technique was found to cause maximum disease severity . .for biological control of the Pathogen 20 isolates of Trichoderma harzianum and one isolate of Pseudomonas fluorescence were tested in vitro. The isolate Th16 and Th14 were found to inhibit maximum mycelial growth of the pathogen. Many plants and their products are known to have antifungal activity. Such plant product may be suitable to fit in the frame work of integrated management of collar rot disease of lentil. Castor and Ashwagandha leaf extract at 5%, 1 0% and 20% concentration inhibited the maximum mycelial growth of S. rolfsii, followed by Lantana camara and Aloe vera. Mustard oil cake extract was found most effective, controlling 100% mycelial growth of the pathogen in vitro. Whereas castor and karanj oilcake extr.acts inhibited the growth of pathogen significantly. The cold water extract of Azwain seed was found more effective against the pathogen as compared to hot water extract, which inhibited the radial growth of pathogen efficiently. The complete inhibition of mycelial growth of Sclerotium rolfsii was found with Propiconazole, Tabuconaz.ole, Hexaconazole, Ridomil and Carbendazim+ Mancozeb at all ~0.03%, 0.05% and 0.1 %) concentrations. Other fungicides (Captan, Mancozeb and Carbendazim) also showed significant inhibition of the mycelial growth of the pathogen. No inhibition was recorded in the treatment with copper oxy chloride even at 0.2% concentration.