Nutrient content affecting Spodoptera frugiperda and Dalbulus maidis occurrence in corn

摘要

This work aims to study the effect of the nutrient contents in the leaves of corn on the incidence of Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) and Dalbulus maidis (Delong & Wolcott) (Homoptera: Cicadellidae). The treatments were represented by unfertilized corn plants and corn plants fertilized with 250 kg of the formulation 4-14-8 (N-P-K) + 100 kg of ammonium sulfate (AS)/ha and 500 kg of the formulation 4-14-8 (N-P-K) +200 kg of AS/ha, arranged in randomized blocks with four replicates. Attacks by 5. frugiperda and D. maidis were higher as the nitrogen, sulfur, calcium and copper content in the leaves of corn increased. The effects of calcium and copper found in this study were not consistent with that of lower susceptibility associated with higher levels of these nutrients mentioned in the literature. We believe that there was a cumulative effect of the nutrients altogether, building up a nutritiously better vegetable which in turn had less reserve for defense, or that the content of both nutrients in the leaves were not high enough to induce such effects.