Effects of Four Insecicides on Immature Stages of Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) Egg Parasitoid of Tuta absoluta (Meyrick) (Lep.: Gelechiidae)

The effects of the recommended dose (RD) and half of recommended dose (HRD) of four insecticides, abamectin, emamectin benzoate, acetamiprid and flubendiamide, were studied on different immature stages of Trichogramma evanescens, egg parasitoids of tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae). Parasitized eggs of the Angoumois grain moth, Sitotroga cereallela (Lepidoptera: Gelechiidae), were treated by the dipping method at the larval, prepupal, or pupal stages of the parasitoid. Cards containing 140 parasitized eggs of Sitotroga cerealella (Lepidoptera: Gelechiidae) were dipped into RD and HRD solutions of the insecticides for 10 seconds at each developmental stage of the parasitoid. Bioassay was performed only for immature stages of F0 generation. Reduction in emergence rate, parasitism rate and longevity of F0 generation as well as reduction in emergence rate and sex ratio of F1 generation were determined. Acetamiprid and flubendiamide were harmless at pupal stage, abamectin, emamectin benzoate and acetamiprid were slightly harmful but flubendiamide was harmless in regards of the emergence rate of the generation F1. Flubendiamide was the only insecticide with no significant difference on sex ratio compared to control. Both concentrations of abamectin and emamectin benzoate were slightly harmful and flubendiamide was harmless in terms of the rate of emergence and parasitism at the generation F0 in all developmental stages. In general, abamactin and flubendiamide in both generations were in slightly harmful and harmless groups, respectively.