Efeito da irradiação UV-C sobre Sitophilus zeamais Motschulsky, 1885 (Coleoptera: Curculionidae) em milho armazenado

Abstract

Corn (Z. mays L.) is one of the main grains produced in Brazil, intended for both human and animal consumption. However, when grain storage is carried out inadequately, it contributes to insect and fungal attacks that result in losses in nutritional and commercial value. Thus, alternative control measures can be employed to reduce chemical residues in the grains and to ensure the health of rural workers. This research was necessary to evaluate the effect of UV-C irradiation time on S. zeamais in stored corn. The experiment was conducted in a pest resistance evaluation chamber at the Agricultural Sciences Center (CCA), under controlled conditions. A colony of S. zeamais was maintained by the weekly addition of chemically untreated corn kernels. The experiment was designed in a completely randomized experimental design with 7 treatments (0, 10, 20, 30, 40, 50, and 60 minutes of UV-C irradiation on infested grains). Each treatment had 5 replications, with each plot consisting of a plastic container containing 15 grams of corn kernels infested with S. zeamais. The 35 plots were randomly arranged inside a storage cabinet without lighting. The plots were evaluated every 30 days, when insect counting took place. Subsequently, the data were evaluated through regression analysis, obtaining the regression curve and the determination coefficient. The number of insects decreases linearly between 10 and 20 and between 30 and 50 minutes of exposure to ultraviolet irradiation, contributing to the decrease in grain weight loss, which occurs linearly between 10 and 40 minutes, stabilizing between 40 and 60 minutes of ultraviolet irradiation exposure. UV-C light irradiation negatively affects the growth of the S. zeamais population, reducing the weight loss of stored corn grains.