Compatibility of four insecticides with parasitoids of Spodoptera frugiperda (Lepidoptera: Noctuidae) in Nayarit, Mexico

Abstract

In Mexico, corn cultivation is the basis of the diet, with a surface of 6.7 million hectares, with an average yield of 6.6 Mg<middle dot>ha -1 . The objective was to evaluate the most widely used insecticides for the control of Spodoptera frugiperda on the entomofauna associated with corn. A 900 m 2 experimental area was used in the Academic Unit of Agriculture of the Autonomous University of Nayarit during one crop cycle. The insecticides were: chlorpyrifos ethyl, cypermethrin, methomyl and spinetoram, plus a control, in a randomized block design with four repetitions. Plants where insecticides were not applied showed a parasitism rate of 27,5 \%, and the main non -target species affected were Pristomerus spinator , Campoletis sonorensis and Cotesia sp. aff. Scitula. In the experimental units treated with insecticide, the rate of parasitism was 0 \%. Methomyl insecticide (carbamate) was the most aggressive against nontarget organisms followed by chlorpyrifos ethyl (organophosphate) while spinetoram (spinosins) was the least aggressive. General active ingredients such as carbamates and organophosphates represent a risk for the diversity of natural enemies.