Controle de Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) e desempenho produtivo de genótipos de milho Bt

Abstract

The fall armyworm, Spodoptera frugiperda (J. E. Smith 1797) is considered a major maize pest. Currently, its control is carried out using maize genotypes with Bacillus thuringiensis Berliner technologies that confer resistance to plants and chemical and biological insecticide applications. Thus, the purpose of this work was to evaluate the yield performance of Bt maize hybrids, under field conditions with damage of the fall armyworm. The trial was developed at the Experimental Farm of Agricultural Sciences, Federal University of Grande Dourados - UFGD, located in Dourados - MS, in the 2018/2019 summer crop season, with a completely randomized block design with four replications. Six treatmentes (five Bt maize hybrids and a non-Bt hybrid) were evaluated, with and without control of the fall armyworm, in a factorial design (6x2). Every five days the number of live caterpillars was counted, the visual damage scores were assigned and at the end of the experiment the productive performance of the genotypes was evaluated with the following technologies: Herculex®, Leptra®, Powercore®, Viptera 3®, VT PRO 3® and non-Bt hybrid. The mean number of larvae was compared by contrasts of the negative binomial model, at 5% probability. The data of mean damage score were compared by Friedman test, also at 5% probability and the means of data regarding productive performance were compared by Kruskal-Wallis test, at 5% probability. In the evaluations of number of larvae and average damage scores in maize plants, there was generally a lower incidence and lower damage caused duo to the larvae feeding on the hybrids containing the Leptra® and Viptera 3® technologies and for the productive parameters there was no significant difference between the hybrids studied, even with and without chemical control of the pest. It is concluded that there are maize hybrids resistant to S. frugiperda, but the pest did not affect the productive performance of the plants in the infestations that occurred in the study.