~ 1596 ~ Journal of Entomology and Zoology Studies 2019; 7(1): 1596-1599 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2019; 7(1): 1596-1599 © 2019 JEZS Received: 26-11-2018 Accepted: 30-12-2018 SK Singh Organic Farming Research Centre, SKUAST-J, Chatha, Jammu and Kashmir, India Vishaw Vikas Research Scholar, Division of Soil Science & Ag. Chemistry, SKUAST-J, Chatha, Jammu and Kashmir, India Reena ACRA, SKUAST-J, Dhiansar, Jammu & Kashmir, India Satesh Kumar Organic Farming Research Centre, SKUAST-J, Jammu and Kashmir, India N Panotra Organic Farming Research Centre, SKUAST-J, Jammu and Kashmir, India Amitesh Sharma Organic Farming Research Centre, SKUAST-J, Jammu and Kashmir, India Correspondence Reena ACRA, SKUAST-J, Dhiansar, Jammu & Kashmir, India Relative efficacy of Bacillus thuringiensis against Spodoptera litura (Fab.) on Okra grown under differential organic manure application SK Singh, Vishaw Vikas, Reena, Satesh Kumar, N Panotra and Amitesh Sharma 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. 3 rd , 5 th and 7 th 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. Keywords: Bacillus thrunigenesis, Spodoptera litura (Fab.) Abelmoschus esculentus, organic nutrient management Introduction Plants supplied with nutrients from organic sources, biological materials have been reported to be more resistant to insects as compared to those grown with chemical fertilizers [1] . Workers are also of the view that pest outbreaks are likely to be reduced with organic farming practices, because of the establishment and maintenance of healthy soils in such fields [2. 3] . Recent researches have proved the plants resistance to insect-pest and diseases is related to the biological, physical and chemical properties of the soil [4, 5] . Signalling between soil and plants have also been reported to be mediated by soil organic matter, which may help in pest management [6, 7, 8] . Farming practices that results in nutritional imbalances in plants have been reported to lower pest resistance [9] . Soil nutrient availability besides affecting the amount of plant damage from herbivores, also affects the plant ability to recover from such damage [10] . Soil fertility status also impacts the physiological susceptibility of crop plants to insect-pest either by affecting the individual plant resistance to hervibores attack or by altering plant acceptability to them. 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. Okra is used as a boiled vegetable; it is rich in minerals and vitamins. Okra is principally infested with okra fruit and shoot borer (Earias vitella and Earias insulana) Helicoverpa armigera, Spodoptera litura, jassids, whiteflies, etc. Spodoptera litura is becoming serious presently on several important crop plants including okra. The larva of S. litura is hairless, variable in colour (young larvae are light green, the later in stars are dark green to brown on their backs, lighter underneath); sides of body with dark and light longitudinal bands; dorsal side with two dark semi-lunar spots laterally on each segment, except for the prothorax; spots on the first and eighth abdominal segments larger than others, interrupting the lateral lines on the first segment. Though the markings are variable, a bright-yellow stripe along the length of the dorsal surface