Assessing Corn Plant Health

May 14, 2003 10(9):70

Joe Lauer, Corn Agronomist

Assessing plant health after a destructive event such as flooding, hail, frost or insect feeding is important for replant decisions. This past week many acres were temporarily flooded and in some parts of northern Wisconsin frost occurred Monday morning. Often these events damage the exposed leaves, but will have little or no effect on the belowground growing point or final seed yield.

To assess plant health after a destructive event and for making a replanting decision:

  1. Wait 3 to 4 days
  2. Observe growing point. If color is white to light yellow then plant is alive. If you suspect the plant is not healthy or questionable, count as ½ of a plant for population purposes.
  3. Consult replanting chart. (in Wisconsin Crop Manager 10(7):56-57)

Flooding at any time when the growing point is below the water level can kill the corn plant in a few days, especially if temperatures are high. Growing point tissues are depleted of oxygen. Frost should not be a problem with corn until the growing point moves aboveground around V5 to V6.

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