Interspecific larval competition of two diabrotica species (northern and western corn rootworm) in corn roots: Implications for pest management

Authors: WANGILA, DAVID - University Of Minnesota; Pekarcik, Adrian; WANG, YUCHENG - University Of Minnesota; YANG, FEI - University Of Minnesota

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2026
Publication Date: 1/24/2026
Citation: Wangila, D.S., Pekarcik, A.J., Wang, Y., Yang, F. 2026. Interspecific larval competition of two diabrotica species (northern and western corn rootworm) in corn roots: Implications for pest management. Plants. 15(3). Article 15030367. https://doi.org/10.3390/plants15030367
DOI: https://doi.org/10.3390/plants15030367

Interpretive Summary: The western corn rootworm (WCR) and northern corn rootworm (NCR) are the two major belowground insect pests of corn in the U.S. Corn Belt. These species coexist in the same habitat, where their larvae feed on corn roots, increasing the risk of plant damage and yield loss. Understanding larval competition between WCR and NCR is crucial for effective management of these pests. Two independent greenhouse trials were conducted to evaluate competition between WCR and NCR. Results showed that WCR consistently exhibited higher emergence rates than NCR, and that WCR is more competitive than NCR. Within species, competition resulted in a male-biased emergence in NCR, whereas WCR sex ratios largely remained balanced. The competitive dominance of WCR, coupled with changing weather patterns, may facilitate its northward expansion across the U.S., potentially displacing NCR populations and further spreading Bt and rotation resistance that increase crop damage. Such changes could exacerbate pest management challenges in corn production systems. Integrating knowledge of corn rootworm competition, biology, resistance development, and climate change will be critical for developing informed management strategies to mitigate CRW damage in agroecosystems effectively.

Technical Abstract: The western corn rootworm (WCR) and northern corn rootworm (NCR) are the two major belowground insect pests of corn in the U.S. Corn Belt. These species coexist in the same habitat, where their larvae feed on corn roots, increasing the risk of lodging and yield loss. Understanding larval competition between WCR and NCR is crucial for effective insect resistance management and integrated pest management. To assess interspecific larval competition, two independent greenhouse trials were conducted by infesting non-Bt corn plants with varying egg ratios of diapause and non-diapause populations of both species. Results showed that WCR consistently exhibited higher emergence rates than NCR, regardless of the initial egg infestation ratio. The observed ratio of NCR to WCR in both diapause and non-diapause groups was significantly lower than expected, suggesting that WCR is more competitive than NCR. Within species, competition resulted in a male-biased emergence in NCR, whereas WCR sex ratios largely remained balanced. The competitive dominance of WCR, coupled with climate warming, may facilitate its northward expansion across the U.S., potentially displacing NCR populations and further spreading Bt and rotation resistance. Such changes could exacerbate pest management challenges in corn production systems. Integrating knowledge of corn rootworm competition, biology, resistance development, and climate change will be critical for developing informed management strategies to mitigate corn rootwormCRW damage in agroecosystems effectively.