Drip chemigation of flonicamid effectively controls cotton aphid (Aphis gossypii) and is benign to lady beetle (Coccinella septempunctata) and lacewing larva (Chrysoperla sinica)

Abstract

Cotton can suffer from injury and yield loss caused by the cotton aphid (Aphis gossypii Glover). Current control of this pest relies heavily on insecticides, which is associated with hazardous effects on non-target organisms, environmental pollution, and pest resistance. The present study examined the efficacy of drip chemigation of flonicamid, a systemic insecticide, to control the cotton aphid and evaluated its effect on two natural enemies of aphids, seven spotted lady beetle adults (Coccinella septempunctata L.) and green lacewing larvae (Chrysoperla sinica T.) in a cotton field in Xinjiang, China in 2016 and 2017. The results showed that flonicamid applied via drip chemigation (700 g a.i. ha−1) effectively controlled cotton aphid for 40 days compared to 20 days when applied through foliar spray (75 g a.i. ha−1). Drip chemigation of flonicamid was safer to the two natural enemies compared to foliar spray. Additionally, the cost of drip application of flonicamid was lower than foliar spray as cotton plants were commonly irrigated via drip system in Xinjiang. Our results show that drip chemigation is much simpler, cheaper, and safer for application of flonicamid and more effective in aphid control compared to a conventional foliar spray, although the rate of flonicamid applied through drip irrigation was substantially higher than the foliar application.