Life-stage-dependent side effects of selected insecticides on Trichogramma cacoeciae (Marchal) (hymenoptera: Trichogrammatidae) under laboratory conditions

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is classified as one of the most harmful pest of tomato crops. Many species of predators and parasitoids including Trichogramma cacoeciae (Marchal) (Hymenoptera: Trichogrammatidae) are noted as potential candidates used for biological control of this pest. Therefore, the use of selective insecticides is critical to conserve and protect natural enemies in the field. This study assessed the side effects of insecticides on different development stages of T. cacoeciae under laboratory conditions. For this, eleven pesticides such as: Indoxacarb, spiromesifen, cyromazin, chlorfenapyr, cypermethrin, diafenthiuron, chlorantraniliprole, spinosad, azadirachtin, Bacillus thuringiensis (Bt) and virus HaNPV were tested. This study shows that indoxacarb, spiromesifen, chlorfenapyr, cypermethrin, diafenthiuron and spinosad had a negative effect on immature stages of Trichogramma. All insecticides residues on tomato leaves were found to be toxic to Trichogramma adults except azadirachtin, Bt and virus HaNPV. Therefore, the use of the tested natural products (azadirachtin, Bt and HaNPV) at the recommended doses is viable, having no negative impact on T. cacoeciae in tomato crops.