Resistance evaluation of maize varieties to Sitophilus zeamais infestation across two generations: Insights for Integrated Pest Management

Sitophilus zeamais (Coleoptera: Curculionidae), the main pest of stored corn grains, represents a significant challenge for agriculture. The use of resistant corn varieties appears as an effective control alternative, minimizing dependence on synthetic chemical insecticides. In this study, we evaluated the resistance performance of eight maize varieties to S. zeamais over two generations. The experiment was conducted without choice, where 50 g of grains of each variety were infested with 15 adult insects. After a period of ten days for mating and oviposition, the adult insects were discarded and the F1 generation was evaluated. Adults from the F1 generation were used to infest the grains of each variety from the F2 generation. The parameters evaluated included the total number of insects emerged, insect weight, grain mass loss, longevity, average biological cycle and susceptibility index. The results revealed significant differences between the varieties in terms of resistance to S. zeamais. In a separate experiment, with a choice option, arenas containing eight Petri dishes were used, each with 50 g of grains of each variety. 120 adult insects were released in the center of the tray. In this scenario, BRS 451 QPM corn showed resistance through the antixenosis mechanism, while Al-Bandeirantes exhibited antibiosis effects on S. zeamais insects. The results highlight the importance of evaluating the resistance effects of varieties on more than one generation of insects to confirm the resistance or susceptibility status of a variety. The corn varieties indicated as resistant in this study can be used as an environmentally friendly alternative to reduce S. zeamais infestation and minimize economic losses. Furthermore, these varieties can be incorporated into genetic improvement programs to develop future commercial cultivars resistant to S. zeamais.