Evaluating Last Week’s Freeze Damage in Corn & Small Grains

Rome Ethredge – UGA Interim Grains and Soybean Agronomist

 

Corn

Corn affected by cold is growing out of it in deep southwest Georgia where we had 4 hours of freezing temperatures 12 days ago with a low of 28.7 degrees F. It was colder as you went north and more hours below freezing.

After the freeze event since the growing point wasn’t killed and we’ve had warm temperatures, we have lots of growth and what I’ve looked at so far looks OK. We still need to watch how the corn plants unfurl, hopefully they won’t get too caught up and have trouble breaking free. This corn was flat on the ground with the tops dead-on Monday (3/14) and now on Thursday (3/17) it’s looking much better. The top is still dead but since the growing point survived the leaves have grown and pushed up out of the ground.

If we get to the point of having to decide whether to replant some corn, we need to carefully consider the percent of stand affected, the original yield goal, value of inputs already applied, and potential yield loss from a later planting date prior to making any replant decisions.

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Small Grains

We may see freeze damage in wheat and oats grown for grain. This is what we’re looking for according to the growth stage in the following chart:

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Most of what we have now in Georgia is in the Joint stage. When we cut the stem in half with a knife, we will find the small grain head maybe 5 inches high. It will be small and if it’s discolored, yellowish, mushy, has a bad smell then the grain head is affected, and yield will suffer. See photo below, figure 7. See other things to look for in the above chart.

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The 2 photos below are ones that I took today from a wheat field in Decatur County, Georgia. It is wheat that was planted too early and is more advanced that we would like to have this early in the year.

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The second photo of is a healthy head where the plant was in the flag leaf stage, so the head was wrapped in the leaf and it looks like it’s going to be ok. It was hard to see this before today, day 4 after the freeze.

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Thanks to Dewey Lee, State Executive Director, Georgia Corn Growers Association, for assistance with the above articles.