EFFECT OF NEEM LEAVES AS SOIL AMENDMENT ON SOUTHERN BLIGHT DISEASE, GROWTH AND PHYSIOLOGY OF CHILI

Abstract

A pot experiment was conducted to evaluate the effect of Sclerotium rolfsii inoculation and soil amendment with leaves of Azadirachta indica A. Juss. on southern blight disease, growth and physiology of chili (Capsicum annuum L.). The highest disease incidence (60%) and plant mortality (46%) were recorded in positive control where S. rolfsii was inoculated without soil amendment. Application of lower doses (1% and 2%) generally enhanced disease incidence. However, in 3% soil amendment, minimum disease incidence (27%) and plant mortality (27%) were recorded. S. rolfsii significantly reduced root and shoot growth as well as leaf chlorophyll and protein content. None of the soil amendment treatments significantly improved crop growth over positive control treatment. However, 3% soil amendment significantly enhanced chlorophyll content over positive control. In contrast, all the soil amendment treatments significantly declined leaf protein contents as compared to negative and positive control treatments. Application of different doses of A. indica significantly enhanced polyphenol oxidase (PPO) and peroxidase (PO) activities as compared to both the control treatments. This study concludes that soil amendment with 3% dry leaves of A. indica significantly decreased disease incidence and plant mortality in chili caused by S. rolfsii, possibly by enhancing production of defence related enzymes viz. PPO and PO.