Biologia de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) em algodoeiro de fibra colorida tratado com silício

Abstract

The caterpillar Spodoptera frugiperda (Smith) is a key pest of the corn culture and each year its occurrence in the cotton culture has increased, causing severe damage from the seedling phase to maturation. The objective of this work was to evaluate the effect of the silicon on the biology of S. frugiperda in white and colored fiber cotton plants. The bioassays were conducted with two cultivars of cotton, BRS Cedro (white fibers) and BRS Verde (green fibers), with and without silicon application. The silicon was applied as a solution of 1% silicon acid, at a dosage equivalent to 3 ton/ha of SiO2 . The following biological parameters were evaluated: larval mortality, duration of the larval and pupal phase, pupal viability, pupal weight, gender ratio, adult longevity of males and females and the number of eggs/female. It was verified that the silicon application only increased the mortality of caterpillars fed with BRS Cedro leaves, not demonstrating any effect on the caterpillars when applied on BRS Verde. Furthermore, the BRS Cedro cultivar, when compared to the BRS Verde cultivar, presented a lower pupal weight and a lower eggs/female production.