Demographic Studies for Evaluating the Side Effects of Insecticides Proteus® and Pymetrozine on Variegated Lady beetle Hippodamia variegata (Goeze)

Abstract

Variegated lady beetle Hippodamia variegata is considered as an important biological control agent. There is a need to use pesticides in combination with biological agents to get a better controlling result in some cases. In this study, various stages of the predator were exposed to the sublethal concentration (LC30) of two insecticides, Proteus® and pymetrozine. Results showed that the duration from adult emergence to the first oviposition (APOP), as well as the total preoviposition period (TPOP) from egg stage to the first oviposition day (TPOP) of the predator was also significantly increased after exposure to sublethal concentrations of both insecticides. The intrinsic rate of increase (r) was 0.195 ± 0.005 and 0.191 ± 0.007 day-1 in pymetrozine and Proteus® treatments, respectively, which are significantly lower than the control (0.225 ± 0.005 day-1). Conclusion, this study revealed that at sublethal concentration, Proteus® could adversely affect the predator at a demographic level.