Do neonicotinoids better than pyrethroids for Coccinella septempunctata L. (Coleoptera: Coccinellidae)? A comparative sub-lethal indirect age-stage, two-sex life tables laboratory bioassay

Abstract

Insecticides are the most economic and quick tool to control harmful agricultural insect pests which reduce crop productivity. However, these insecticides have a suppressive and negative impact on non-targeted beneficial fauna. The efficiency and mode of action of numerous insecticides are also much diverse. Therefore, we studied the sublethal impact of bifenthrin (pyrethroids) and clothianidin (neonicotinoids) on ladybird beetle Coccinella septempunctata L. (Coleoptera: Coccinellidae), taking these insecticides as the model representative for the insecticide groups. Our results revealed that both insecticides enhanced the life length of male and female adults of ladybird beetle as compared to control treatment. Bifenthrin reduced the survival rate of larvae and adults as compared to clothianidin and control as well as lowered the fecundity rate of C. septempunctata. After control treatment, the developmental period of each larval instar was shorter in clothianidin than bifenthrin. Adult emergence was also less in clothianidin than in the control group. However, clothianidin triggered the fecundity of the female ladybird beetle. Higher fecundity was recorded in clothianidin treatment as compared to bifenthrin and control which means clothianidin is a better option in integrated pest management (IPM) program as compared to bifenthrin involving the ladybird beetle as a natural biocontrol agent.