Sublethal and transgenerational effects of insecticides used in whitefly control on biological traits of the parasitoid Eretmocerus hayati

Eretmocerus hayati is an effective biocontrol agent against whitefly Bemisia tabaci. Thiamethoxam, abamectin, and sulfoxaflor are the commonly used insecticides for whitefly control. We explored the sublethal and transgenerational effects of these insecticides on E. hayati in laboratory by exposing the parental pupae to the maximum field-recommended concentration of each insecticide. The adult longevity and host control efficiency of F0 generation treated with insecticides decreased significantly compared with control. Demographic characteristics, parasitism and host-feeding rate of E. hayati F1 progeny was analyzed using the age-stage, two-sex life table, and the CONSUME-MSChart computer program. The results indicated that most life traits of E. hayati F1 generation, including the development duration of immature, longevity of female adults, oviposition days and fecundity were negatively affected by thiamethoxam. However, except for the prolonged development duration of pupae, no significant negative effect on other demographic parameters or population parameters of E. hayati F1 generation were observed in both abamectin and sulfoxaflor groups. The net host-feeding rate and whitefly-killing rate (parasitism + host-feeding) of E. hayati F1 females were adversely affected by thiamethoxam but not affected by abamectin and sulfoxaflor. Thiamethoxam had the most severe sublethal and transgenerational effects on E. hayati of the three insecticides tested. However, abamectin was more compatible with release of E. hayati, especially when applied during the E. hayati pupal stage. These findings provide insights into comprehensively understanding of the effects of insecticides used in whitefly control as well as the integrate management of B. tabaci.