Comparative toxicity and economics of some pyrethroid and non-pyrethroid insecticides against cotton bollworms

Abstract

Field plot studies were conducted in Madhya Pradesh, India, in 1985-86, to compare the efficacy and economics of sprays of the pyrethroid insecticides Ripcord 10 EC (cypermethrin), Fenval 20 EC (fenvalerate), Pay-Off 10 EC (flucythrinate), and Mavrik 25 EC (fluvalinate), all applied at 75 g/ha, fenpropathrin 10 EC at 60 g/ha, and Decis 2.8 EC (deltamethrin) at 16.8 g/ha, with the non-pyrethroid insecticides Ekalux 25 EC (quinalphos) at 270 g/ha, Amitraz 20 EC at 240 g/ha and Thiodon 35 EC (endosulfan) at 420 g/ha against the noctuid Heliothis armigera [Helicoverpa armigera] and the gelechiid Pectinophora gossypiella on the cotton variety Khandwa-2 which was sown on 26 June 1985. The insecticide treatments were applied at the start of cotton flowering again 6 weeks later at formation. Plots treated with fenvalerate had the lowest percentage pest damage (0.013), followed by those treated with flucythrinate (0.012), deltamethrin (0.0028), cypermethrin (0.0125) and fluvalinate (0.0012). The highest yield was recorded in plots treated with fenpropathrin (26.43 q/ha), followed by those treated with fenvalerate (26.39 q/ha) and flucythrinate (25.95 q/ha). The highest cost-benefit ratios were recorded for plots treated with fenvalerate, endosulfan, fenpropathrin, and flucythrinate. It is concluded that fenvalerate is the most effective and economic treatment for the control of H. armigera and P. gossypiella on cotton.