Inter-and intra-specific competition between corn rootworm: Insights for pest management

Understanding larval competition between two major underground corn insect pests, the western corn rootworm (WCR) and the northern corn rootworm (NCR), is crucial for insect resistance management and integrated pest management. The two pests co-exist in corn systems, where larvae feed on roots, affecting water and nutrient uptake, and adults feed on silk, affecting pollination. Two independent greenhouse trials were conducted to assess larval competition between WCR and NCR by infesting non-Bt corn plants with different egg ratios of diapausing and non-diapausing eggs of both species. Results showed that survival rates for non-diapausing populations were greater compared to diapausing ones, suggesting that a longer diapause might negatively impact the fitness of corn rootworm larvae. Additionally, there was a higher emergence of WCR adults compared to NCR, indicating a potential competitive advantage for WCR. The study highlights the importance of monitoring and managing WCR populations due to their competitive edge, especially in fields that have a mix of both species. In the context of corn rootworm resistance to Bt and an upsurge of NCR in some fields, sustainable pest management approaches are required to manage and mitigate corn rootworm damage.