DEVELOPMENT OF SPRAY SCHEDULE INVOLVING COMMERCIAL AND INDIGENOUS BIOPESTICIDES FOR INSECT PEST AND DISEASE MANAGEMENT IN SOYBEAN CROP

Abstract

Application of natural biopesticides in organic production system reduces the amount of toxic synthetic pesticide use in farming and help minimizing chemical leaching, thus, protect and conserve environment to a great extent. A field experiment was conducted during kharif seasons (rainy) of 2008-2011 to evaluate the efficacy of different biopesticides against major insect pests and diseases of susceptible soybean variety (JS-80-21) in mid hills of Meghalaya. Nine biopesticide treatments  comprising Neem oil 3 ml/l, Panchagavya (combination of five products of cow milk and excreta viz., cow milk, curd, ghee, urine and fresh dung) 3%, Beauveria bassiana 4 g/l, Derisom 2 EC (a product of Derris indica commonly called karanjin) 3 ml/l, anosom 1 EC or annonin (a product of Annona mucosa called Custard Apple) 3 ml/l, Panchagavya 3% + Lantana leaf extract 10% + Vermiwash 10%,Derisom 3 ml/l + Panchagavya 3%, Derisom 3 ml/l + Panchagavya 3% + Cow urine 3% and untreated control were tested against soybean rust (disease), leaf folder and Myllocerus spp. Results revealed that significantly the least rust disease index (34.9%), Myllocerus spp. (0.61) and leaf folder population (0.36) with high seed yield (0.87 t/ha) were observed with Derisom 3ml/l + Panchagavya 3% + cow urine 3%and the maximum pest and disease incidence were observed with untreated control (45.8%, 1.38, 0.51, 0.63 t/ha). Among the biopesticides, Beauveria bassiana (4 g/l) was the least effective in controlling disease (9.3%) and insect pests (1.02 and 0.44 for Myllocerus spp. and leaf folder, respectively) as well as gave the lowest soybean seed yield (0.71 t/ha). However, all the organic biopesticide products were superior to control. However, Derisom 3ml/l + Panchagavya 3% + cow urine 3% was found to be the most effective in managing rust disease and population of Myllocerus spp. and leaf folder with high seed yield. Thus, environment friendly management with these biodegradable organic products will lead towards sustainable organic crop production in studied ecosystem of north east India.