Don’t Lose Your (Wheat) Head

Don’t Lose Your (Wheat) Head

Heavy rains could mean you need to take action to save yield


Much of the wheat crop across Midwest America has come to a head. This close to the finish line, it is important to make sure you protect your crop from damaging issues.

“Anything that could go wrong did go wrong in our wheat crop,” says Ruth Becks, South Dakota State University agronomy field specialist.

The season started with significant challenges that caused variations in many stands. Fields may have some sections that are flowering and others that have barely come to a head. This means farmers have even more difficult decisions coming their way.

“All of a sudden we got a lot of moisture. Stripe rust, tanspot and even Fusarium Head Blight can be an issue,” explains Becks.

Moisture breeds fungus and disease and with non-uniform stages in fields treatment could be difficult. Two major yield robbers to watch for are stripe rust and fusarium head blight (FHB).

Stripe rust can cause 50% or more yield loss. When untreated it can be a total yield loss. Some areas conditions set the stage for a stripe rust infestation.

Look for small yellowish pustules to appear in linear rows on the leaf. A single infection can result in a stripe the length of the leaf. Pustules can also occur in the spike. Stunting of plants is common with severe early infections, according to USDA Agricultural Research Services.

FHB cost more than $2.6 billion to U.S. agriculture in the 1990s. This severe epidemic opened many eyes to the threat FHB brings to cereal grains.

With FHB, you have to spray before you have an infection, says Becks. There is no real rescue option. She suggests referring to the Fusarium Head Blight Prediction Center to see what the risk is in your area. This on line tool can help farmers with decisions related to fungicide applications for FHB.

If you waited too long to spray and notice FHB or scab in your fields you’ll see premature bleaching in spikelets. At times FHB will infect the entire head but in many cases just a few florets will be infected by the fungus. In moist environments pink/salmon colored spores may appear on the rachis and glumes of spikelets, according to the American Pytopathological Society. Scab prefers extended periods of high moisture or humidity. Wheat fields infected with FHB will often not yield well. Grain from plants infected from FHB is shriveled and has a white chalky appearance. These kernels are often referred to as “tombstones”.

You’re scouting, but when is the best time to apply fungicide?

There are typically three times farmers apply fungicide, says Becks.

1.End of tillering or Feekes 4-5- this application prevents early leaf spotting diseases. This is recommended especially when wheat is planted in wheat residue.

2.When the flag leaf is fully extended or Feekes 9. The flag leaf contributes up to 75% of the yield. It is essential to keep it green and healthy as long as possible.

3.During early flowering or Feekes 10.51—This timing is very difficult to plan because flowering will occur over a period of time in any wheat crop, even in years when the crop is uniform, which is not the case this year. I always recommend farmers err on the side of early rather than late with this fungicide application. This fungicide application can protect the plant from scab and also protect the flag leaf.

While scouting for fungus and disease keep your eye open for late season weeds. It may be too late to get them this year but you can take care of them before they cause yield loss next season.

Walk, look and see what is out there. Actively scouting for problems is an important part of successful crop production, suggests Becks.

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