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Three Things to Watch in Winter Wheat
As the winter wheat crop enters a pivotal time of rapid growth, there are several things wheat producers need to watch.
Weather. Up to now, this unusually mild weather has prompted the crop to green up and begin growing from two to three weeks earlier than normal. When it enters this growth phase, the crop uses a lot of moisture, and many areas of the Winter Wheat Belt don't have a lot of excess moisture to begin with. And with little rain in the forecast, soils could be depleted in a hurry.
Rainfall amounts of a trace in Texas, western Oklahoma, and western Kansas, to 0.75-inches to 1.5-inches in southern Kansas and central Oklahoma, respectively, probably aren't enough to quench the thirst of this rapidly advancing wheat crop.
However, the forecast does call for cooler temperatures later this week and next. If that coolness is accompanied by dampness (rain, fog, or dew), that could lead to the next problem . . .
Diseases. Already, stripe rust and leaf rust are occurring in Texas (in sentinel plots near Amarillo, 100% leaf rust, up to 90% stripe rust on susceptible varieties) and Oklahoma (stripe rust northwest of Oklahoma City). Bob Hunger, Oklahoma State University Extension wheat pathologist, believes stripe rust will continue to increase in incidence and severity in his state, with other diseases not far behind. "Leaf rust and powdery mildew also can be found on lower leaves and will continue to increase if we continue to have weather favorable for disease development," he notes in his March 12 Wheat Disease Update newsletter.
In addition, tan spot is occurring in wheat fields containing a lot of crop residue. Most likely, these tan spot spores survived through the mild winter.
With the outlook for strong south winds, and possible cooler and damp weather, these wheat diseases will most assuredly move north. It is imperative that wheat farmers keep an eye on weather forecasts and pay attention to disease monitors from state Extension offices and prepare to make a fungicide application. And most importantly - scout fields for foliar disease activity! And while you're there, look for . . .
Weeds. A host of summer annual weeds (kochia, Russian thistle, buckwheat) are appearing in the wheat. You must pay close attention to the wheat 's growth stage before making herbicide applications, says Dallas Peterson, weed specialist at Kansas State University. Dicamba is effective on these crops, but it must be applied between the 2-leaf and jointing stages. It will provide some residual control of these weeds.
Other herbicides that can be applied prior to jointing include Agility SG, Beyond (on Clearfield varieties only), Olympus, Orion, PowerFlex, Pulsar, Rage D-Tech, and Rave.
Growers can apply MCPA and 2,4-D. MCPA is safer prior to tillering; wait to apply 2,4-D until after the wheat is well-tillered to avoid stunting the crop. The best odds of success for 2,4-D are between full-tiller and jointing.
There is an assortment of herbicides to apply until flag leaf is visible: Affinity BroadSpec, Affinity TankMix, Ally Extra SG, Express, Harmony +2,4-D or MCPA, Harmony Extra, and Supremacy. Through flag leaf stage, opt for Huskie, Weld, and WideMatch.