INSECTICIDE RESISTANCE VARIATION IN HELICOVERPA ARMIGERA (HUBNER) IN COTTON AND TOMATO CROPS

摘要

The study deals with insecticide resistance levels in Helicoverpa armigera (Hiibner) to eight commonly used insecticides in cotton and tomato ecosystems in India. The experiments were carried out by leaf spray bioassay against the laboratory and fieldpopulations of 3rd instar larvae of H. armigera. Results showed that for field populations of H. armigera, the LC_(50) of abamectin, chlorpyriphos, cypermethrin, indoxacarb, malathion, quinalphos, spinosad and triazophos was 74.09, 1421.04, 170.72, 381.28, 1678.10, 1772.20, 83.90 and 2684.97 ppm, respectively in cotton ecosystem while it was 46.44,1294.89,167.81, 288.00, 850.41, 1678.10, 91.49 and 2515.37 ppm, respectively in tomato ecosystem. These results when compared with that of laboratory populations showed the increased resistance of H. armigera against the insecticides under laboratory conditions and the increase in insecticides resistance in H. armigera on cotton over tomato for the tested insecticides was found to be 37.30, 8.87,1.70, 24.46,49.30, 5.30, -9.0 and 6.30 per cent, respectively.