Warm fall and harvest losses contribute to widespread volunteer corn
Many fields across the region are showing notable levels of volunteer corn this fall. While volunteer plants are not uncommon, the amount seen this year is greater than usual. This rise is linked to weather conditions and crop stress that caused uneven kernel development and tougher harvest conditions in 2025.
Several factors contributed to rapid crop maturity this season. A large share of corn was planted early, and many areas experienced excessive rainfall during key growth stages. This was followed by warm and humid temperatures in midsummer, which pushed reproductive development ahead while also allowing southern rust to spread. These stresses led to lighter test weights and corn ears that were harder for combines to thresh effectively. When grain fails to separate cleanly, it can fall behind the combine and later sprout as volunteer corn. Even a small number of kernels per square foot can represent a full bushel of yield loss per acre.
Warm fall weather further encouraged seed to germinate. Temperatures across September and October were well above normal, and timely rainfall helped volunteer plants grow quickly. Some fields saw plants reach nearly 12 inches before frost arrived.
Looking ahead to the 2026 season, farmers should consider several implications. Volunteer corn can serve as a host for insects like corn rootworm, which may lay eggs near the base of living plants. If the volunteer plants originate from Bt hybrids, reduced toxin expression could allow larvae to survive. Volunteer plants may also carry diseases such as tar spot and northern corn leaf blight into the next growing season.