How do European corn borers primarily damage corn plants?

European corn borers primarily damage corn plants by feeding in the stalks during their larval stage. The larvae, which hatch from eggs laid on the corn plant, penetrate the stalks and tunnel through them as they feed. This feeding behavior disrupts the plant’s vascular system, leading to reduced nutrient and water transport, which can ultimately impair the plant's growth and yield. The damage can also create entry points for secondary pathogens, increasing the risk of disease.

While the roots are critical to the plant's health and stability, the primary damage caused by European corn borers occurs above ground in the stalks rather than in the roots. Adult borers typically do not feed on the corn plant; instead, they focus on reproduction after emerging from the pupa stage. Therefore, the significant impact of the European corn borer is closely tied to the larval stage and the specific parts of the plant they target.