CONTROL OF STEMPHYLIUM BLIGHT (Stemphylium botryosum) OF ONION THROUGH SELECTED FUNGICIDES AND PLANT EXTRACTS FOR SEED PRODUCTION

Abstract

A field experiment was conducted at the research farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during the rabi season of 2007-08 to study the control of stemphylium blight (Stemphylium botryosum) of onion for seed production through some selected fungicides, plant extracts and micronutrients. The experiment was laid out in a Randomized Complete Block Design (RCBD) with 3 (three) replications. An onion variety BAR! Piaj-l was used in the experiment. Treatment of onion bulb followed by foliar spraying with nine treatments comprising Rovral 50WP, Dithane M-45, Ridomil Gold, Bavistin 50WP, Cupravit 50WP, Neem leaf extract and Alamanda leaf extract along with micronutrients and Control were explored in the experiment. In in vitro experiment (cup method) Rovral 50WP proved to be the best in controlling the radial mycelium growth of Stemphylium botryosum. In field condition, bulb treated with Rovral 50WP (0.2%) followed by foliar spraying at 7 days interval starting from onset of the diseases minimized disease incidence, severity and increased seed yield followed by Dithane M-45. Neem leaf extract showed better performance than Alamanda leaf extract in controlling Stemphylium blight of 'onion. The micronutrient along without spraying of fungicides and plant extracts had significant effect compared to control.