First analysis of genetic diversity and population structure among different geographic populations of the vector of the Corn stunt disease, Dalbulus maidis (Hemiptera: Cicadellidae), in subtropical Argentina

The corn leafhopper, Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) is the vector of the Corn stunt disease, caused by a complex of pathogens, a serious threat to corn production in tropical and subtropical regions of the American continent. The aim of this study was to conduct an exploratory analysis to estimate the structure and genetic differentiation of D. maidis populations from three geographical regions collected during two maize growing seasons in northwestern Argentina using inter-simple sequence repeats (ISSR) markers. Populations in the High-elevation Valley and Dry Plain sites, despite being geographically separated by mountains of high elevations, were genetically similar, while the nearest populations located in Dry Plain and Humid Piedmont were the most genetically different. The results suggested that populations of D. maidis in subtropical maize-growing areas are structured according to the climatic conditions, mainly humidity and precipitation. Additionally, this structure might be influenced by annual migrants from northern tropical areas, as well as by individuals that occasionally survive from one season to the next as occurs in the Humid Piedmont. Darker body coloration of females sampled during the second year in Dry Plain and Humid Piedmont might be associated with colder temperatures during the winter before maize cultivation. This study is the first conducted in Argentina on the genetic diversity of populations of D. maidis. The results presented here highlight the need for further investigation into the origin and potential movement of D. maidis populations. Knowing how the crop is colonized will aid in the development of well-fitting models, for preventing the disease caused by the pathogens transmitted by this insect.