Freeze Damaged Wheat Underscores One Key Planting Decision

Image of winter wheat damaged by freezing temperatures in April 2018 ( Kansas Wheat Commission )

This year’s wheat crop has encountered widespread challenges due to frost.

Farmers across the Midwest have experienced freezes this week and past weekend, while farmers in the Midsouth are still reeling from a mid-April freeze that proved to be worse than expected.

If freeze injury cripples your 2020 crop, you might wonder how you can hedge your bets next year.

“You’re going to get a freeze every five or 10 years,” says Phil Needham, owner of Needham Ag Technologies based in Kentucky. “We don’t recommend planting wheat before the hessian fly date. We always suggest growers plant fuller season maturity varieties first and earlier maturity varieties later–this helps reduce spring freeze injury by delaying the jointing and heading dates by a few days. That strategy was the difference between minimal and severe damage this year.”

Most of the severe damage he’s seeing this year is in early planted or early maturing varieties. If you’re in an area with winter wheat, check on plants to see just how much yield you’ve lost.

“In early April we had some abnormally warm weather,” Needham says. “We had some 82 to high 80s Fahrenheit temperatures so that got the wheat growing a little bigger than what it should have been for the calendar date.”

Then, disaster struck when Mother Nature hit the region with a cold snap on April 15. Areas were down in the low 20s, and farmers are still realizing just how much damage was done in the Midsouth.

“Bottom line, some of the wheat that had headed out in some of the fields, or fields that were partially headed, had significant freeze injury as a result of those cold temperatures,” Needham says. “We need 500 to 600 good heads per square yard. So if we’ve lost 50 of 100 heads, and some fields have more than that, then there’s a proportional decline in yield.”

For farmers in the Midwest, this past weekend and week’s freeze events mean those farmers will also need to keep a close watch on wheat fields.

Scouting How-To

Damage in wheat depends on three major factors:

  1. Temperature
  2. Longevity of the cold snap
  3. Stage the wheat is in

If the wheat is farther along, say headed, like it was in southern states during April’s cold snap, you’re likely to see greater yield damage.

If your fields are headed, check the heads for damage. If they were fully emerged from the boot and freeze damaged, the head will be pale, limp and damage will be evident. If partially emerged, even if the emerged portion shows significant damage, the portion in the boot could still be viable.

“The other concern we’ve got is some of the stems are damaged, some of the nodes are damaged, which will likely give us some standability issues closer to harvest,” Needham says. “However, it’s really important that you give the plant adequate time to make a good determination, that generally five to 10 days of warm weather.”

For farmers in the Midsouth, you can already check fields. Farmers in the Midwest might need to wait a few days to get a good idea of the extent of damage to wheat fields.

Even in less mature fields, those that haven’t headed out, freeze damage from just two hours of exposure can lead to massive stem damage and ultimately standability issues.

“If you have 75% head damage or more that’s marginal to keep and you’ll need to talk with your insurance agent to figure out what your options are,” Needham advises. “If you’ve just got 40% or 50% damage it’s probably worth keeping, but you’ll need to assess this on a region by region basis.”

When scouting, check multiple locations to get a good feel for what’s going on in the whole field. Use drones and other tools as appropriate to get a whole-field view.

What Should You Do Next?

For farmers in the Midwest with wheat not yet headed, you might think about planning a fungicide pass to help the weakened crop.

“It’s important to go ahead and protect these plants with a foliar fungicide,” Needham explains. “Look at your fields and make an objective decision on if you should spend where you have freeze damage and if you want to protect fields without freeze damage. Once you have determined the freeze damage isn’t severe, plan on applying a foliar fungicide at flowering stage to protect the wheat from Fusarium–or head scab as it is also known.”

Read more weather news here:

Use Imagery and Boots on the Ground to Scout Freeze-Damaged Fields

Prevent Plant in South Dakota, North Dakota Could Rival Last Year

Worst Cold Snap Since 1966 Has Farmers Assessing Potential Damage