Harmful to Parents, Harmless to Offspring: Lethal and Transgenerational Effects of Botanical and Synthetic Insecticides on the Egg Parasitoid Trichogramma atopovirilia

This study investigated the lethal and transgenerational effects of botanical and synthetic insecticides on the egg parasitoid <i>Trichogramma atopovirilia</i>, an important natural enemy of <i>Spodoptera frugiperda</i> in Brazil and beyond. The treatments were assessed for their impact on parasitism, emergence, sex ratio, and flight capacity of adults exposed to contaminated eggs. The botanical insecticide ESAM (ethanolic seed extract of <i>Annona mucosa</i>) significantly reduced the parasitism in the F₀ generation by 99.76%, categorizing it as toxic. Anosom^® [acetogenins (annonin as a major component)] and Azamax^® [limonoids (azadirachtin + 3-tigloilazadirachtol)] also caused substantial reductions (99.13% and 92.36%, respectively) in the parasitism rate. EFAMON (ethanolic leaf extract of <i>Annona montana</i>) reduced the parasitism by 62%, while the synthetic insecticide Premio^® (chlorantraniliprole) resulted in a 28.21% reduction. In the F₁ generation, emergence rates for EFAMON, Azamax^®, and Premio^® exceeded 70%, showing no significant differences from the negative control (82%), while Anosom^® resulted in a lower emergence rate of 61.39%. No significant effects were observed on sex ratio or parasitism in the F₁ and F₂ generations. Most adults reached high flight capacity (above 80%). These results indicate that while ESAM was toxic, the other treatments showed no transgenerational effects. Our findings contribute to understanding insecticide selectivity and highlight the importance of such studies for the sustainable management of <i>S. frugiperda</i> within integrated pest management programs.