P-111. Efficacy of Nuclear Polyhedrosis Virus against Helicoverpa armigera Hubner on cotton in Haryana

Cotton is a premier eco-industrial crop of summer season in northern plains of India which generates sizeable employment. Among the four commonly cultivated species of cotton, American cotton (Gossypium hirusutum L.) is the most widely grown genotype which is attacked by about a dozen major pests. Out of these, Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) is a serious pest infesting this crop. Several insecticides like endosulfan, triazophos etc. are recommended for its control, however, insecticide resistance, environmental hazards and residual effect on non target organisms led to shift the trend towards non- chemical control. Amongst these, studies on the use of nuclear polyhedrosis virus (NPV), its formulation and field testing against H. armigera has been made in various parts of India. Accordingly, a field trial was conducted on cotton for two years to evaluate the effectiveness of local isolate of NPV of H. armigera and compared with B.t. (1 Kg/ha) and endosulfan (0.07%). Cotton var. ‘H-1117’ was sown following recommended agronomic practices. Nine treatments viz. HaNPV @ 250, 500, 750 LE/ha, HaNPV (250) + half dose Endosulfan, HaNPV (500) + half dose Endosulfan, HaNPV (750) + half dose Endosulfan, Endosulfan 35EC (0.07%), Ganganagar HaNPV and control were applied to crop during evening hours with three replicates (plots) per treatment (Area per plot= 5m × 4 m). Pre treatment population varied between 0–6 larvae per plant with an average of 2.72 larvae per plant. Post treatment population varied between0- 1.66 larvae per plant with an average of 0.47 larvae per plant. Weight of cotton lint varied between 100 to 2300 g per plot in different treatments. Treatments HaNPV (500 LE) + half dose Endosulfan, HaNPV (750 LE) + half dose Endosulfan found promising for future studies as post treatment count and cotton lint weight was 0.11, 0 larvae per plant and 1766, 1833 g per plot, respectively.