Análise comportamental biológico dos Sitophilus zeamais (Coleoptera: Curculionidae) em diferentes cultivares de milho

Abstract

The maize weevil, S. zeamais, is one of the main pests of stored corn grains in Brazil, due to the damage caused to the crop and the negative effects associated with its infestation. The objective of this study was to evaluate the resistance of seeds from commercial (F2) and landrace maize cultivars to S. zeamais attack. Bioassays were conducted using choice and no-choice tests, in a completely randomized design (CRD), with nine treatments and six replications. The treatments consisted of five cultivars derived from commercial F2 varieties (Tevo: T-1680 and T-1503; Forseed: FS-533 and FS-560; popcorn maize; and

Morgan 616) and three landrace varieties (Cunha, Cateto, and Cacetinho). In the no- choice test, adults were confined with the grains to evaluate the biological parameters of

S. zeamais. The shortest mean developmental time was observed in T-1503 (30.70 days) and T-1680 (31.52 days). The highest susceptibility index occurred in T-1503 (13.66) and FS-533 (11.99), whereas T-1680 showed the lowest value (4.76). The highest multiplication rate was observed in T-1503 (3.50) and the lowest in T-1680 (0.33), following a pattern similar to that observed for the instantaneous population growth rate. The greatest weight losses occurred in T-1503 (72.75%) and FS-533 (68.94%), whereas the lowest losses were recorded in T-1680 (8.93%) and popcorn maize (7.17%). In the choice test, the FS-533 treatment showed the highest mean preference (29.18%), while the lowest values were observed in Cateto (2.85%), Morgan (0%), and T-1503 (0%). Overall, the T-1680 genotype presented the lowest values for most of the evaluated variables, characterizing it as the most resistant to S. zeamais attack.