Research methodology and levels in the resistance categories in soybean genotypes to Heliothis virescens (Fabricius, 1781) (Lepidoptera: Noctuidae)

Abstract

In the last seasons the losses in soybeans from attacks of Heliothis virescens (Fabricius, 1781) (Lepidoptera: Noctuidae) has increased because it is a pest of difficult control and by its crescent migration to the crop. Hence, studies aiming to identify resistant soybean genotypes and standardize a research methodology specific to this pest insect are needed. Thus, this study aims to evaluate research methodologies and levels of resistance categories in soybean genotypes against H. virescens. For the standardization of a specific research methodology for the insect, trials of attractiveness and feeding preference will be performed. The following factors will be assayed: density of larvae more adequate to leaf discs; structure and age of plants more favorable to the larvae; regarding the oviposition preference, the number of pairs per cage and age of plant more favorable to oviposition will be tested; for the antibiosis test, different densities of insects and containers, and plant structure more adequate for the trial will be also assessed. Basing on the results, the optimal methodology will be determined to be used in subsequent tests of attractiveness, feeding and oviposition preference, and antibiosis in soybean genotypes against H. virescens. A completely randomized design will be used in all tests. The antibiosis and research methodology assays will be set in a 3 x 2 factorial arrangement, with three densities of insects and two containers. (AU)