Morphological and molecular characterization of Brazilian populations of Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) and the evolutionary relationship among species of Diatraea Guilding.

Abstract

The sugarcane borer or corn stalk borer, Diatraea Guilding is polyphagous insect pest of many important crops such as corn, sorghum and sugarcane. Losses arising from the attack of Diatraea species have been a serious problem, which may cause loss in sugarcane production around 0.25% in sugar, 0.20% in alcohol and 0.77% of body weight for every 1% infestation and up to 21% in corn production fields. In Brazil, the most commonly reported species are Diatraea saccharalis (Fabricius, 1794) and Diatraea impersonatella (Walker, 1863) (= D. flavipennella). However, multiple other species of Diatraea have been identified in Brazil according to the literature. Currently, little information exists on the presence of the other species causing injury to sugarcane and corn. The objectives of this study were to improve the accuracy of species assignment, evaluate the population genetic structure, and address many of the outstanding questions of systematics and evolution of Brazilian populations of D. saccharalis. To address these main questions, classical taxonomic methods were used, focused on morphological characterization of the reproductive organs, especially the male genitalia. In addition, genetic studies were performed using simple sequence repeats (SSR) and a fragment of cytochrome C oxidase subunit I (COI) gene. The data and findings from this research will contribute to the understanding of evolutionary aspects of insect pests in order to develop more effective and sustainable population management practices.