Soil characteristics and agricultural management shape the community composition of the white grub complex (Coleoptera: Melolonthidae) in native maize agroecosystems

Root herbivores such as white grubs (Coleoptera: Melolonthidae) severely reduce maize yields worldwide. However, root-feeding white grubs belong to a complex of similar-looking soil-dwelling larvae that also include species that feed exclusively on dead organic matter, as well as species that feed on both roots and dead organic matter. This complexity in the ecological guilds of white grubs should be considered when developing pest management strategies for root-feeding white grubs. In the present study we investigated the effects of soil characteristics and management practices on white grub communities and root damage in maize. The abundance and composition of white grubs were analysed on twelve maize plots under three management strategies (conventional, crop rotation, and organic fertilization). Our results showed that soil characteristics were the main factors influencing the composition of the white grub community, but agricultural practices also significantly impacted the abundance and prevalence of specific genera. For example, Phyllophaga spp. was present in all systems, whereas Cyclocephala spp. showed high abundance in plots where synthetic fertilization was applied. Our results suggest that management strategies targeting white grubs need to account for local soil conditions, as community responses emerge from the interaction between agricultural practices and edaphic heterogeneity. • White grub communities are determined by agricultural management and soil heterogeneity • Agricultural management is not sufficient to homogenize the soil in maize plots • Phyllophaga thrives in all plots, while Cyclocephala only in synthetic fertilized plots • Management practices show potential to reduce root damage