Corn plants gave all they had in some fields this year to make as much corn as possible. When they ran out of nutrients in the soil or the roots couldn't get to more nutrients due to dry weather, the stalks began pulling nutrients from other parts of the plant.
One place the plant pulls from to finish corn kernels near the end of the season can be the stalk. Plants will cannibalize stalks in order to produce as many viable corn kernels as possible. As far as the corn plant knows, the ears it produces will be seed, not feed or food.
Danny Greene with Greene Crop Consulting, Inc., Franklin, believes that many weakened stalks he found early in the fall, before last week's rains, for example, were due to cannibalization, not stalk rot.
"You could split stalks open and unless you found corn borer damage in non-GMO corn, the pith still looked healthy in most cases," he says. "We really hadn't had the weather to that point that would favor stalk rot development. I believe that many of the plants simply needed more nutrients than they could get from the soil and started pulling them from the stalks."
A simple push test confirms that stalks are weak. If you push them and they crease at the bottom and won't snap back, the stalk is weakened and prone to lodging. It would be a good field to mark for early harvest if that happens consistently in a field, Greene says.
However, it doesn't mean that stalk rot caused it to happen, he emphasizes. Before you blame it on stalk rot, look for other symptoms. For management purposes, it's important to know which type of stalk rot is in the field. They may come in later, but right now, he believes you'll discover that it isn't stalk rots – just plants that gave all they had to produce an ear.