Spatio‐temporal dynamics of corn rootworm, Diabrotica spp., adults and their spatial association with environment

Multiyear and multilocation studies were conducted to investigate the within‐ and the between‐year spatial dynamics of corn rootworms Diabrotica spp. (Coleoptera: Chrysomelidae), adults and their spatial associations with environmental factors in cornfields. Grid‐based spatial sampling was conducted by trapping adults emerging from the soil (i.e., ‘emergence‐trap counts’) and by counting the number of adults in the ear zone of corn plant (i.e., ‘ear‐zone count’). Spatial analysis with distance indices (SADIE) was used to determine spatial distribution patterns and to investigate spatial associations. Ear‐zone counts and emergence‐trap counts were spatially dynamic within a year and more frequently aggregated in the middle of growing seasons and random early and late in the season. However, during the peak population periods, spatial distribution of ear‐zone counts and emergence‐trap counts were significantly consistent between years, indicating predictability of future spatial distributions. Spatial distribution of emergence‐trap counts and ear‐zone counts were positively associated with soil moisture and presence of corn plants with silks, respectively. This study demonstrated that within‐year spatial distribution patterns were dynamic and that there was between‐year spatial consistency of corn rootworm adult distributions. Such information can be used to improve preventative management of corn rootworms.