Relative efficacy of Bacillus thuringiensis against Spodoptera litura (Fab.) on Okra grown under differential organic manure application

Abstract

Okra, Abelmoschus esculentus have an important place among kharif vegetable crops grown in all the states of India and has appreciable nutritional and economic value. This crop is used as boiled vegetable and is rich in minerals and vitamins. Field experiment on the influence of Bacillus thuringiensis kurstaki (Dipel 8L) against Spodoptera litura (Fab.) in okra managed through organic treatments was conducted during Kharif 2016 and 2017 at the Organic Farming Research Centre, OFRC, SKUAST-J, Chatha.. Bacillus thuringiensis var. kurstaki (B.t.) is the most commonly used bio-pesticide globally. A field experiment was conducted using ten organic nutrient treatments in variety Jammu Okra -05 (Seli Special) during Kharif 2016 and repeated in Kharif 2017 at Organic Farming Research Centre, Chatha, SKUAST-J. B.t.k. was applied at the rate of 1.0 L/ha sprayed at 15 days interval. The relative efficacy of bio-pesticide, Bacillus thuringiensis kurstaki @ 2g/L was evaluated against S. litura at different days viz. 3rd, 5th and 7th days after spray, in ten different organic manure applications with Farm Yard Manure (FYM), Vermi-compost (VC), Poultry Manure (PM) and Neem Cake (NC) alone, as well as their different combinations. Results revealed that maximum reduction of larval population was recorded in the okra crop grown on 12 kg Farm Yard Manure + 1.75 kg Poultry Manure, followed by FYM + Neem Cake.