As recent weather has lead to cooler temperatures across the region, there is concern about frost injuring emerged corn and soybeans. Temperatures at 32 degrees may result in injury to leaf tissue. However, when temperatures reach 28 degrees for two hours, there is likely plant death, said Wayne Flanary, field specialist in agronomy for the University of Missouri Extension.
“Corn has its growing point below the soil surface. Corn will regrow provided the freezing temperatures are not extremely low. Clear nights are those conditions, which temperatures can drop to extremes,” states Flanary in a release. “If frosted, wait seven days to determine regrowth. Larger plants will have the green leaf tissue showing in the whorl.”
To examine smaller plants, Flanary suggests cutting the growing point with pocket knife and looking for clean, white tissue. If clean and white, plants will typically survive. If yellow and discolored, they likely will die.
Corn regrowth after frost injury is impacted by temperatures and sunshine.
“Cloudy, wet conditions may result in increased plant death as plants need sunshine to recover. Also, tilled fields have higher injury compared to untilled fields. We need to wait and scout fields for recovery,” he said.
As far as soybeans, injury, if present, will be noticeable at the hypocotyl, the sensitive part of the soybean plant as the cotyledons emerge.
“Soybeans can handle lower temperatures, but the growing points are exposed. Larger soybeans may regrow from the unifoliate buds. Scout soybean fields for survival,” states the release.
For more information, call Flanary at 279-1691.