Combined effect of abamectin and imidacloprid against three insects of cotton

Cotton is the most important crop around the world. It is damaged by different types of insect pests including pink bollworm, aphids and also affects the yield production. A laboratory experiment was conducted to investigate the effects of two insecticides abamectin and imidacloprid along with their mixture (abamectin + imidacloprid) at recommended concentrations against Pectinophora gossypiella (chewing type), Aphis gossypii (sucking type) and Coccinella septempunctata (chewing type) at temperature 28 ± 2 °C, relative humidity 65 ± 5% and photoperiod 12:12 (light:dark). Insecticide mixture (abamectin + imidacloprid) was the most effective against cotton aphid which revealed 83.13–99.13% mortality, while abamectin and imidacloprid showed mortality 65.97–83.90% after 3 days. Results indicated that imidacloprid was the most toxic against pink bollworms which showed 67.19–83.30% mortality, while abamectin was the least effective against pink bollworm and exhibited only 22.05–45.06% mortality after 3 days. Mixture of abamectin and imidacloprid had a significant effect and exhibited upto 99.73% mortality after 3 days. In case of ladybird beetle, abamectin was the least effective after 1 day and 15.69–25.48% mortality was observed, while highest mortality (53.48–80.08%) was observed with insecticide mixture (abamectin + imidacloprid) 3 days of postapplication. Mortality and concentration were found to be correlated positively. These findings suggest that a combination of these insecticides at highest concentrations might be efficient and useful for controlling sucking and chewing insect pests of cotton.