Desempenho de cultivares de milho em relação à lagarta-do-cartucho

Abstract

The genetics of maize cultivars is one of the factors that influence on damage level caused by fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae); however, there is no information about performance of commercial cultivars for this pest attack. The aim of the present research was to identify maize cultivars less damaged by the fall armyworm under field conditions, which could be used as an additional tool for managing the pest in areas with history of high infestations, as well as for genetic breeding programs. The experiments were accomplished during the summer season 2006/2007 and 2007/2008; and off-season 2007, in Capão Bonito (SP), Coroados (SP) e Tatuí (SP). Two experiments were set up in each area, one with simple and triple hybrids (HST) and other with double hybrids and varieties (HDV). The experimental design was in randomized blocks, with three and four replications for HST and HDV, respectively. The leaf injury caused by fall armyworm under natural infestation was evaluated using a rating scale ranging from 1 to 10. There were significant differences among cultivars for leaf injury, with the cultivars DKB 390 (simple hybrid) and DKB 979 (triple hybrid) being less damaged. These cultivars may serve as potential sources of resistance against the fall armyworm.