Effect of lambdacyhalotrin and methomyl on the biology of Spodoptera frugiperda   (Smith) (Lepidoptera: Noctuidae)

MORILLO F, NOTZ A. 2004. 2004. Effect of lambdacyhalotrin and methomyl on the biology of Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Entomotropica 19(1):7-14. Research was conducted to evaluate the effect of the insecticides lambdacyhalotrin and methomyl on the biology of Spodoptera frugiperda (Smith) strains, exposed to selection pressure. Two strains of S. frugiperda were exposed simultaneously to the insecticides during nine generations. Additionally, we kept control strain not exposed to selection pressure. Development time of the egg, larval, pupal and adult stages in each strain, as well as the fecundity and fertility were recorded. The duration of the larval and pupal stages was significantly longer in the lambdacyhalotrin-selected strain (EIL) and the methomyl-selected strain (EIM) compared to the control strain, from the first to the last generation. The longevity of males and females only showed differences in some generations in the strains exposed to insecticides. The developmental period from egg to adult was longer in the EIL and EIM strains than in the control. The fertility diminished to 50.61 and 47.31% in the last generation, in the EIL and EIM strains, respectively. Results indicated that the differences in the duration of some of the insect phases represent a reproductive deterioration in compensation of the survival to the process of selection pressure with the insecticides lambdacyhalotrin and methomyl