Comportamento de genótipos de milho geneticamente modificados em relação aos danos causados por Spodoptera frugiperda

Abstract

This study aimed to evaluate the agronomic behavior and laboratory suppression of the Spodoptera frugiperda caterpillars from different cultivars and technologies of Bt corn (Bacillus thuringiensis). Therefore, two experiments were carried out, one at field level, using eight genetically modified maize cultivars in an experimental area of the Dois Vizinhos Campus of the Federal Technological University of Paraná. The experimental design used was randomized blocks, with 3 replications of each material. The variables analyzed were: attacked plants and damage level, based on the Davis scale, height, moisture, mass of a thousand grains, rows per ear, grains per row, grains per ear and yield. The second experiment was carried out at the Biological Control Laboratory of the same institution, where Spodoptera frugiperda caterpillars in the first instar were fed circular leaf fragments from eight genetically modified hybrid maize cultivars and one non-Bt cultivar for five consecutive days. The experimental design was completely randomized with five replications and the parameter evaluated was the daily mortality of caterpillars. On average, cultivars with the Leptra technology had a lower proportion of plants attacked and level of damage by the cartridge caterpillar. In the laboratory, all genetically modified cultivars caused higher mortality on caterpillars compared to the non-Bt cultivar. The average yield of the hybrids evaluated was 13,338.09 kg ha-1, and only the hybrid AG9025 showed significantly lower yield compared to the others.