The plant gives priority to the kernels, and will cannibalize other plant tissues if necessary to meet this need. During this period of high demand, the ability of the plant to produce new carbohydrates through photosynthesis is essential. Any stress that reduces that ability will result in the translocation of carbohydrates from root and stalk tissues to the ear. This weakens those tissues and allows root and stalk rot pathogens to invade. Leaf diseases, insect feeding and hail reduce the leaf area available for photosynthesis.
Cloudy weather reduces the sunlight available for photosynthesis.
If good growing conditions during ear and kernel formation are followed by moisture stress later on, the problem is worsened. Low soil fertility. Nutrient imbalance caused by low potassium and high nitrogen increases losses from stalk rot. If nitrogen is available early but is lost before the end of the season, stalk rot may be increased dramatically. Insect feeding, especially corn rootworms and corn borers.