Within-field spatial patterns of Helicoverpa zea(Lepidoptera: Noctuidae) and spatial associations with stink bugs and their injury in field corn

The corn earworm, Helicoverpa zea(Boddie) (Lepidoptera: Noctuidae), is a cosmopolitan pest in the field crop landscape in the southeastern United States. Field corn (Zea maysL.) is the most important midseason host for H. zeawhere intensive selection pressure occurs for resistance to insecticidal toxins from Bacillus thuringiensis(Bt). Because spatial patterns of H. zeain field corn have not been extensively studied, field corn was sampled for H. zealarvae and injury in 2021 and 2022. Patterns of spatial aggregation were identified in a number of fields in both larval populations and injury. Aggregation of H. zealarvae was less common at R5 than at R2. Associations between the spatial patterns of H. zeaand the variability in crop phenology were identified in some fields, with positive associations between plant height and H. zealarvae, indicating that ovipositing H. zeamoths avoid areas with reduced plant height and delayed reproductive maturity. Additionally, negative spatial associations between stink bug ear injury and H. zealarvae and their injury were found in a small number of cases, indicating some spatial interactions between the two pest complexes and their injury. Results from these studies provide valuable insight into the spatial patterns of H. zeain field corn. An understanding of the local dispersal and population dynamics of H. zeacan be used to help further improve integrated pest management and insect resistance management programs for this major polyphagous pest.