Farm Progress

A number of challenges, from pest infestations to weather anomalies, make the winter wheat season difficult.

Walt Davis 1, Editor

December 30, 2016

3 Min Read
UP AND GROWING: The 2017 Kansas winter wheat crop got off to a good start in parts of the state with ample rainfall. Much of the wheat in other areas, especially in northwest and north-central Kansas, was drought-stressed, and emergence was spotty. Wheat streak mosaic has been a challenge in some regions as well, and other problems include a December cold snap, with temperatures below zero, no snow cover and poor root development.

One of the most frustrating things about growing winter wheat is the length of the growing season (nine or 10 months) and the myriad assortment of perils it can face during that season.

Anything from insect problems to diseases, and weather problems from drought to high winds, freezing temperatures, hail and extreme heat are part of almost every growing season.

So far, the 2017 crop has been challenged by a fall drought that has resulted in poor emergence and a shallow rooting system over parts of state and, in mid-December, by subzero temperatures and winds exceeding 50 mph with scant snow cover.

"The frustrating part of possible winter injury is that you have months to wait to know the true extent of the damage," says Vance Ehmke, a producer in Lane County. "The damage doesn't show up in full until spring green-up."

For growers like Ehmke in northwest Kansas, drought has already been a fall struggle, along with an early appearance of wheat streak mosaic during an abnormally warm fall without a frost until late November.

The good news is that the mid-December polar plunge to subzero temperatures was preceded by at least some days that dropped to near freezing and was followed by at least two days of subfreezing temperatures that have guaranteed that the wheat curl mites that are the vector for wheat streak mosaic will not overwinter in Kansas. Nor will the sugarcane aphids that plagued the sorghum crop and the Asian lady beetles that followed them into Kansas.

Any or all of those species could survive a one- or two-day cold snap into the low 20s or teens if they were well sheltered in residue or in the johnsongrass that is the winter habitat of SCA. But none of them have the winter-hardiness to make it through a prolonged, subfreezing cold period, which was exactly what Kansas got from Dec. 17 to Dec. 20.

For some Lane and Scott county farmers, the relief from curl mites will help the 2018 crop but not the 2017 crop, some fields of which were already wiped out by wheat streak mosaic by late November. But it does bode well for fields that were only lightly infested and might have the ability to recover from damage.

Ehmke says the drought stress and the poor root structure of the crop, along with the dryness of the soil, are of greater concern for winterkill.

Dry soils tend to freeze faster and deeper than wet soils. And poor root development makes it more likely that all, not just part, or a root will be damaged or killed by extreme cold. Poor root development and dry soil also increase the risk of the wheat plants being literally blown out of the ground by high winds, says Romulo Lolatto, Kansas State University Extension wheat specialist.

Damaged wheat plants that survive the winter still have a chance to thrive if good growing conditions arrive in the spring, enabling secondary tillers to flourish and reach maturity before harvest even if primary tillers have been killed by winter cold or spring frost.

"I like to say winter wheat has nine lives, and sometimes it takes all of them to get to harvest" was a favorite quip of K-State's wheat specialist emeritus Jim Shroyer.

In south-central Kansas, the traditionally highest-yielding area of the state, drought was less severe and in some spotty areas, sporadic rains helped with stands, and root systems had a chance to get better established.

The stressful part for growers is that the threats to the crop are obvious with every weather event, insect infestation or disease arrival during the long growing season from September and October planting to June and July harvesting  but the actual damage — barring total wipeout — really can't be measured until the last loads are weighed at harvest.

 

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