Written by Nick Benson, regional sales manager for Northeast Iowa
Keeping a watchful eye on stalk quality this season may prompt farmers to harvest some corn hybrids before soybeans this fall. Early identification of anthracnose and other stalk rots can help prioritize fields and minimize loss at harvest.
Conditions throughout the summer were nearly ideal for anthracnose: warm, moist weather with extended periods of overcast skies and high humidity. High yield potential and other stresses, such as foliar diseases and insect damage, are often associated with stalk rot as the plant must pull carbohydrates and sugars from other tissues. This cannibalization weakens stalks and roots, making them more susceptible to stalk rot.
Plants affected by stalk rot generally show signs of early death. A shiny, black discoloration develops in blotches or streaks on the stalk surface, particularly on the lower internodes. Internal stalk tissue may become black and soft, starting at the nodes. Lodging typically occurs higher on the stalk than with other stalk rot.