Lethal and sublethal effects of clothianidin, imidacloprid and sulfoxaflor on the wheat aphid,Schizaphis graminum(Hemiptera: Aphididae) and its coccinellid predator,Coccinella septempunctata

The use of pesticides for greenbug,Schizaphis graminumin wheat not only can manage the pest population but also can influence its predator,Coccinella septempunctata. Acute and chronic effects of imidacloprid, clothianidin and sulfoxaflor onS. graminumand its predator,C. septempunctatawere investigated. The results showed that LC(50)of imidacloprid, clothianidin and sulfoxaflor toS. graminumat 48 h was 9.80, 34.29 and 4.40 ml a.i. L-1, respectively, while LC(50)of imidacloprid, clothianidin and sulfoxaflor toC. septempunctataat 48 h was 107.80, 49.52 and 379.26 ml a.i. L-1. Sulfoxaflor and clothianidin were found the most toxic toS. graminumandC. septempunctata, respectively. Tested sublethal doses (LC(10)and LC30) of all insecticides had significant effects on percent repellency of bothS. graminumandC. septempunctata. Sulfoxaflor and clothianidin proved the most repellent toS. graminum(67.00 +/- 2.03% at LC(10)and 86.20 +/- 1.62% at LC30) andC. septempunctata(50.60 +/- 2.81% at LC(10)and 60.00 +/- 3.26% at LC30), respectively. Sublethal doses also demonstrated significant and the lowest percentage reduction in feeding byC. septempunctataonS. graminumin sulfoxaflor treatment (LC10: 4.13 +/- 0.61%; LC30: 5.26 +/- 0.69%). Additionally, sublethal doses reduced body-weight ofC. septempunctataadults emerged from its treated grubs. These results revealed that sublethal doses of sulfoxaflor, imidacloprid and clothianidin negatively affected the biological activities ofS. graminumandC. septempunctataas compared to control. Hence it can be concluded that more attention should be paid towards strategic application of these chemicals as a part of an integrated pest management program for an agro-ecosystem exhibiting maximum activity of coccinelid-predators. Overall, sulfoxaflor proved more appropriate for use againstS. graminuminC. septempunctatamanipulated agro-ecosystem. However,C. septempunctatacompatible integration-strategy for field-application of sulfoxaflor should be devised to enhance its effectiveness againstS. graminumand selectivity againstC. septempunctata.