Assessing Frost Injury of Corn

Growers facing frost injury to corn express concerns whether the corn will recover. When considering frost, its important to consider how low the temperatures dropped. The growing point of the corn plant remains below soil surface until the 5-leaf stage. The location of the growing point provides protection from above ground frost. Corn can easily recover from damage and injury is often limited to the death of the above ground tissue. There should be no yield loss.

However, when air temperatures drop below 28 degrees or less, the growing point can be injured or killed even if the growing point is below ground. It important to understand how low temperatures dropped with the frost.

It is important to assess frost damage by waiting to allow plants to recover. Initally, corn leaves become watersoaked then blackened. Wait three to five days to see if the plants start to regrow. Be aware, if temperatures remain cool, then this will delay your ability to assess injury. New tissue should be growing out of the whorls.

If you have additional acres to plant, continue planting and then after a period of time, determine the extent of injury. The dead tissue of the damaged part of the whorl may cause some problems with leaf growth but, will push on through.

If plants recover, then replanting is not justified. If there areas of dead plants, then replanting may be justified.

For more information, contact Wayne Flanary at 660-446-3724 or Heather Benedict at 660-425-6434, Regional Agronomists, University of Missouri Extension.