How is your wheat crop doing after the freeze? How do you evaluate the possibilities? For some there is nothing much that can be done. But if you have an alternative, what decisions need to be made, what actions need to be taken, and what are the risks that need managed? Call this edition of the farm gate “Failed Wheat Central.”

We will look at a variety of issues, including evaluation of the crop for making decisions, how to eliminate the wheat before planting a new crop, whether to use the crop as forage, pest management before and after, and your all important crop insurance decisions. You won’t get every question answered, but follow the links and you’ll discover more than you ever wanted to know.

Has your wheat crop failed?

In a recent crop production newsletter from the University of Illinois, Specialist Emerson Nafziger writes: “In fields that were in Feekes growth stage 8 (flag leaf emergence) or 9 (flag leaf completely out, or early boot), the growing point (developing head) was 6 or more inches above the soil surface. Many plants this size may not have had the majority of their leaf area killed by the freeze, but stems may have frozen below the growing point, and many such plants have "flopped," ending up nearly flat on the ground due to weakened stem tissue. Dead stem tissue beneath the head means that the head is basically cut off from nutrients and water. Such plants may show green color for some time, but there's little chance that they will recover to produce good yields.” Since it has been more than two weeks since the freeze, you should be able to determine the extent of the damage. Most wheat will have had some leaf damage, but new leaves will emerge and expand. Nafziger adds, “If heads are healthy and stems start to elongate, with a majority of leaf area still intact, then the crop should recover. If any of these is missing, then recovery is unlikely. In any case, however, this period of low temperatures will mean a delay in development of the crop, including later heading and harvest. The crop in the most advanced fields was on pace to head early, so the delay may not be serious. But any delay means, on average, warmer temperatures during development. This could be a problem, especially if it rains during the flowering period.”

The crop is not dead, but is it hurt substantially?

Another crop production newsletter written by University of Illinois Extension Specialist Emerson Nafziger offers several intermediate descriptions of wheat damage to help you pinpoint the status of your crop. In the newsletter, he answers a series of questions. Ask the questions about your crop and try to apply the appropriate answer
• Might here be damage to the head even where it was less than 6 inches above the ground and less than an inch long during the freeze and it still looks healthy? Cold weather when wheat is in the boot stage is usually blamed for heads emerging twisted or even bleached and sterile. We hope that heads as small as many were at the time of the freeze will not show such symptoms, but it might help to split some stalks occasionally over the next few weeks to see if heads are developing normally.
• Can plants grow out of lower stem injury caused by freezing? Though some stem function returned after the freeze, the plant is not able to completely repair damage to its "plumbing," and stems are likely to stay more fragile and subject to breakage where they were frozen.
• What about leaf damage? Many leaves that showed only minor darkening during and after the freeze may have recovered some, but unless leaves have a deep green color, they do not have full photosynthetic capacity.

Will winter wheat in the Great Plains be able to fill properly?

Specialists at the University of Nebraska, in their April 20 newsletter, say, “A major factor in winter wheat yields is the length of the filling period. The longer the filling period, the better the yields. Temperatures above 85°F shorten the filling period and decrease yields. We might estimate a field has 25% freeze injury, but if we have a long cool filling period, we still could have some of our best winter wheat yields. Likewise if we again estimate that the field has 25% freeze injury and the filling period is short with hot weather, yields may be even less than 50% of normal. Freeze injury does delay the onset of winter wheat filling so injured winter wheat yields can be reduced if the weather is hot at the filling stage. Early freeze injury is difficult to evaluate unless it kills the plant. Therefore, growers should be cautious about estimating yield loss as a result of the freezing conditions in early April. Winter wheat is a crop well adapted to the vicissitudes of Nebraska weather and should not be counted out prematurely.”

Should I be filing a crop insurance claim?

Before you destroy it, feed it, or do anything but harvest it, your crop insurance agent needs to know about it, if your wheat crop was insured. This year may be a watershed year in the development of federal rules for crop insurance on wheat, since just about every rule will be tested. Extension Farm Management Specialist Gary Schnitkey at the University of Illinois has provided a comprehensive look at what wheat growers should be doing and what their policies will allow them to do in the wake of the early April freeze. He says if the wheat was not insured, it can certainly be converted to other acreage if warranted. Someone who had signed up for crop insurance on corn can add that former wheat ground to the corn policy for coverage. If your wheat acres were insured an adjuster will want to see some test strips left in the field to later calculate an indemnity payment. On your insured wheat that is being destroyed, you will have the choice of an indemnity payment on the wheat, or insuring the next crop (if you had signed up by the deadline), but you cannot be eligible for insurance on both; and Schnitkey provides an example upon which to base your decisions. For regions with a prevalent practice of double crop soybeans, that soybean crop is eligible for insurance as well as your initial wheat crop. Schnitkey says producers with GRP or GRIP insurance will not have to leave test strips because the indemnity payment is based on the county average. However with many producers expected to destroy wheat in lieu of an alternate crop, the calculations for the indemnity payment will be based on wide variations on planted and harvested acres, and he says destroying wheat acres increases the likelihood and expected amount of GRP and GRIP payments.

Can failed wheat be used as forage?

Forage is a potential use for a failed wheat crop, but with many qualifications. And before any of it is fed to livestock, it needs to be tested for nitrates. At Kansas State, soil fertility specialist David Mengel says the nitrate issue is linked to fertilization, “A very limited number of freeze-damaged wheat samples taken recently have shown high nitrate levels -- 6,000 to 15,000 parts per million (ppm) -- in the forage. The highest values came from fields fertilized shortly before the freeze. Therefore, producers wanting to graze or hay this wheat should test it for nitrates before turning cattle in or cutting for hay. The potential for problems is great.” Nitrate levels higher than 6,000 ppm can potentially be toxic, depending on the situation. Kansas State offers a bulletin on feeding forage from wheat crops that addresses animal health issues.

Extension Livestock Specialist at the University of Illinois Justin Sexten says, “Nitrate toxicity occurs when the animal consumes more nitrate than the rumen microbes can utilize. The rumen microbes reduce nitrate to nitrite which is then converted to ammonia and used by the microbes as a protein source. When the animal consumes forages high in nitrates, excess nitrite is absorbed into the blood and converts hemoglobin into methemoglobin, which restricts the blood's ability to transport oxygen to cells. Animals suffering from nitrate toxicity will exhibit muscle tremors, lack of coordination, and diarrhea. Blood will turn chocolate brown rather than the normal bright red. If symptoms are observed, contact your veterinarian, move the animals to an alternative forage source, and offer grain supplement to speed utilization of the excessive nitrate.” Sexten offers a chart that indicates whether the wheat can be used for forage depending on the percent of nitrate in the dry matter.

How do I eliminate my failed wheat?

Weed Specialist Aaron Hager at the University of Illinois writes in a recent crop production bulletin that before you destroy the wheat to plant a new crop, ensure there is a sufficient interval between application of a wheat herbicide and planting the new crop. That may control what you decide. Any chemical used to kill the wheat should be applied 3-5 days before any tillage operation to allow the wheat to die. Hager offers a number of chemical options to eliminate the wheat prior to planting corn or soybeans.

At the University of Missouri, Weed Specialist Kevin Bradley says the use of Harmony on your wheat will not complicate your transition to another crop, “For the most part, the majority of wheat fields in Missouri are treated with either 2, 4-D or Harmony Extra. As you can see from the table below, if you have treated your wheat crop with either of these herbicides, carryover to corn or soybeans should not be much of a concern. One caveat to this statement is that the previous Harmony Extra label had a 45 day requirement between application and planting of corn or soybeans. Recently, a new supplemental label for burndown use of Harmony Extra in corn or soybeans has been approved which allows for an interval of 14 days between application of this herbicide and planting.” Bradley also provides numerous suggestions for chemical eradication of the wheat prior to tillage.

If you have used a variety of other wheat herbicides, the University of Kentucky provides a list of those with their appropriate intervals for planting corn or soybeans. Some chemicals will not allow another crop to be planted this season.

My wheat is salvageable, but where did the aphids come from?

Disabled by a freeze and limping toward harvest and now your wheat is besieged by aphids. Purdue entomologists John Obermeyer, Christian Krupke, and Larry Bledsoe say the aphids have probably always been in your wheat, but you never had a reason to look for them. They don’t believe the aphids will contribute to further yield losses, nor spread barley yellow dwarf virus. So they say there is little justification for an insecticide application right now. However, scout for the aphids as the wheat heads fill, because 50 or more aphids per head is the threshold for an insecticide treatment. They believe that natural aphid predators may keep the population down without your help.

Will the transition out of wheat bring more insect problems?

Your wheat crop has been home to many insects for the past several months that have appreciated the food supply. Their population and growth stage will probably cause problems as you kill the till the wheat and then plant corn and soybeans which will be quite vulnerable. Entomologists Kevin Steffey and Mike Gray at the University of Illinois believe there is an increased chance for wireworm damage to corn following failed wheat. And they warn users of Bt hybrids that the low level of seed treatment may be insufficient to ward off the wireworms, “Although Bt seed is treated with a low rate of a neonicotinoid insecticide (Poncho 250 or Cruiser Extreme 250), there are concerns that these systemic seed treatments may not afford the desired level of protection against economic infestations of wireworms. Because efficacy data collected from intense wireworm infestations are not plentiful, producers are urged to consider the full spectrum of control choices for this insect pest. An in-furrow application of a granular soil insecticide has been considered the traditional management tactic for heavy infestations of wireworms.”

Summary:
Farming always presents a challenge, and the April freeze will challenge many wheat growers to make hard decisions on whether to stick with their crop and harvest a less than typical yield, or convert the wheat ground to another crop and face new challenges. The ability to make wise decisions is based on good information and how you apply that information which the Extension Specialists have offered in the wake of the freeze. The crop may still be used for a livestock forage, but only if nitrate levels are low. Elimination of the crop will generate challenges on controlling it with herbicides and tillage prior to planting a row crop. Herbicide carryover from wheat to the new crop is a concern for some, as will be a new crop insect pests. Before any action is taken on your failed wheat, your crop insurance agent should be notified, if the wheat was insured.