Seasonal Dynamics of Dalbulus maidis and Occurrence of the Corn Stunt‐Associated Pathogens and Viruses in Field‐Collected Vectors From Commercial Maize Fields in Southern Brazil

Dalbulus maidis is the principal vector of maize stunt‐associated pathogens in the Americas and has become an increasing phytosanitary concern in Brazilian maize production systems, making an understanding of seasonal vector dynamics and pathogen circulation essential for epidemiological surveillance and disease management. This study characterized the population dynamics of D. maidis and the occurrence of maize bushy stunt phytoplasma (MBSP), corn stunt spiroplasma (CSS), maize rayado fino virus (MRFV), and maize striate mosaic virus (MSMV) in field‐collected D. maidis from commercial maize fields in Santa Catarina, southern Brazil. Weekly monitoring was conducted during the 2023/24 growing season across nine municipalities representing main‐ and second‐season maize production systems. Vector abundance was assessed using yellow sticky traps, and pathogen occurrence by molecular screening. Vector abundance differed markedly between production periods, increasing progressively throughout crop development during the main growing season but peaking earlier during vegetative stages in the second season. MBSP increased progressively throughout crop development, particularly during the main season, whereas MSMV showed contrasting seasonal patterns, including higher occurrence during the off‐season and early vegetative stages. MRFV occurred consistently across crop stages, whereas CSS remained comparatively infrequent. Co‐detection of multiple pathogens, particularly MBSP, MRFV, and MSMV, was frequent, indicating overlapping pathogen circulation within field populations of D. maidis . These findings show that maize stunt epidemiology in southern Brazil is shaped by seasonal vector dynamics and the concurrent circulation of multiple pathogens, highlighting the value of integrating entomological surveillance with molecular pathogen detection to support disease monitoring and management.