Colonization and Age Structure of Dalbulus maidis Population in Maize Crops During the Vegetative Stage in the Brazilian Cerrado

Dalbulus maidis is a key pest and vector of maize pathogens in Latin America. Understanding the field population dynamics of D. maidis is essential for improving management strategies and reducing the risk of pathogen transmission in maize. This study evaluated the population density and stage structure of D. maidis across maize vegetative stages and determined the effects of crop development and climatic variables on the abundance of eggs, nymphs, and adults over three growing seasons. Field trials were conducted over three consecutive second-crop seasons (2022-2024) in six commercial maize fields in Jataí, Goiás, Brazil. Insect densities (eggs, nymphs, and adults) were monitored every three days using direct plant inspections, and meteorological data were recorded. Insect populations were assessed from V2 to VT stages, and the effects of plant age, phenological stage, and climatic variables were analyzed using multiple regression models. Results showed that D. maidis egg and adult densities were higher than nymph densities across all seasons. A consistent pattern was observed wherein early maize stages (V2-V4) favoured oviposition and nymphal development, while adults predominated in later stages (V5-VT). There was a positive and significant correlation between adult density and the age and phenological stage of the plants, while eggs and nymphs did not show a significant correlation with age, phenological stage, or climatic variables. These findings have important implications for Integrated Pest Management (IPM), highlighting a critical window early in crop development when monitoring and control actions are likely to be most effective for preventing population buildup and subsequent pathogen transmission.