Abstract
The western flower thrips (Frankliniella occidentalis Pergande), a global agricultural pest, poses a serious crop threat to crops. Chlorogenic acid is a bioactive phytochemical pesticide that controls various insect pests. This study determined the susceptibility of western flower thrips to chlorogenic acid and other common insecticides, as well as the susceptibility of several field-collected populations to chlorogenic acid. Cross-resistance to four common insecticides was also measured. Chlorogenic acid had the highest toxicity of all insecticides tested. All field-collected populations were susceptible to chlorogenic acid, and little cross-resistance was detected between chlorogenic acid and other tested insecticides. Furthermore, analysis of cytochrome P450 enzyme activity in western flower thrips following treatment with LC50 of chlorogenic acid suggests that increased cytochrome P450 activity could be involved in chlorogenic acid detoxification. The sublethal effects of chlorogenic acid were then assessed, and it was found that treatment with LC25 of chlorogenic acid prolonged the duration of two developmental stages, reduced fecundity, and decreased the survival rate of treated western flower thrips compared to untreated insects. Overall, these findings demonstrate substantial toxicity and significant sublethal effects of chlorogenic acid on western flower thrips, suggesting that overexpression of cytochrome P450 genes may be associated with chlorogenic acid detoxification.