CONTROL OF WEEVIL (Sitophilus zeamais MOTSCHULSKY) WITH POWDER OF EPAZOTE (Dysphania ambrosioides (L.) MOSYAKIN & CLEMANTS) IN DIFFERENT GENOTYPES OF MAIZE

Abstract

During postharvest handling of maize (Zea mays L.) significant losses occur due to the attack of storage pests, particularly by weevils (Sitophilus zeamais Motschulsky). The objective of this study was to evaluate the effectiveness of epazote (Dysphania ambrosioides) to control weevil damage in maize. Seeds from 11 genotypes, nine experimental and two commercial, were treated with epazote powder at four concentrations (0, 5, 7 and 10 g of epazote powder kg^-1 of seed) to control weevil. Before treatment, seed moisture content was 13 %, and undamaged seeds indicated the absence of insects. A completely randomized design with a factorial arrangement and three replications was used. The experimental unit consisted of a conditioned plastic box where 100 seeds, previously weighed, were placed along with 50 young weevils and the corresponding dose of epazote powder. The variables recorded were weight loss, damaged grains, and insect survival, all expressed as percentages. There were differences between maize genotypes only for weight loss (P ≤ 0.05); all the maize populations experienced losses; however, hybrid CLTHW14001 was the least affected with 3.5 % weight loss. Doses of 7 and 10 g of epazote kg^-1 of seed caused reduced weight loss, lower damaged grains, and lower insect survival, at 3.4, 12.2, and 3.5 %, respectively. When treated with 7 g of epazote kg^-1 of seed, hybrid CLTHW14001 only lost 0.94 % weight. Epazote powder effectively controls weevil at concentrations from 7 g kg^-1 of seed. The genotype of maize influences the effectiveness of the treatment.