High Hopes for Wheat

Weather Casts Some Concerns

Emily Unglesbee
By  Emily Unglesbee , DTN Staff Reporter
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Kansas and Oklahoma winter wheat fields are in much better condition this spring, thanks to plenty of fall moisture and a mild winter. (DTN file photo by Elaine Shein)

ROCKVILLE, MD. (DTN) -- Cautious optimism is the mood of the season for the Southern Plains winter wheat crop.

A mild winter and plenty of fall moisture has allowed wheat in Kansas and Oklahoma to emerge early and healthy, state wheat experts told DTN. That's a welcome comparison to the 2015 season when wheat growers experienced a harsh winter and weathered continuing drought conditions.

Temperature and moisture trends moving forward will be critical. Both the Oklahoma and Kansas winter wheat crops would benefit from rain, as dry conditions linger in the western regions of both states. Weather conditions over the next month will also determine if existing pockets of stripe rust take off this spring. Finally, late freezes could be especially damaging this year to a crop running one to two weeks ahead of normal development.

FREEZE FEARS

With the country's warmest winter on record wrapping up, it's little surprise that wheat woke up early across the Plains this year.

Depending on planting date and geography, Kansas wheat is ranging in development from Feekes 4 to 7 (second node), which puts the crop roughly a week ahead of schedule for this time of year, said Kansas State University Extension wheat and forage specialist Romulo Lollato. Oklahoma fields are also developing at least a week ahead of their usual pace, according to Oklahoma State University wheat breeder and geneticist Brett Carver.

"If wheat is jointing, temperatures in the low 20s or lower can damage the developing head," Lollato said. "But you need at least two to three hours of temperatures in low 20s (Fahrenheit) for that to happen."

The odds may be in wheat growers' favors this spring, noted DTN Senior Ag Meteorologist Bryce Anderson.

"April in the Southern Plains has an above-normal temperature and above-normal precipitation look to it," he said. "There's very little, if any, cold air indicated from the Canadian Prairies to threaten the wheat crop with a freeze."

With a lowered threat of freezing weather this spring, the wheat crop's early development becomes more advantageous, Carver said. "Accelerated crop development, absent a late freeze, will allow us to take advantage of typically cooler nighttime temperatures later in the grain-filling period," he said.

DISEASE OUTBREAKS POSSIBLE

Stripe rust is already surfacing in fields in Oklahoma and Texas. Thanks to the mild winter, inoculum is present in some Kansas fields, Lollato noted.

How the disease develops depends heavily on weather conditions; it needs cool and wet conditions through flowering to do maximum damage. In Oklahoma at least, "the weather pattern points toward that," Carver said of the state's moisture outlook.

Conditions are drier in Kansas. The state is wrapping up the winter with half its normal precipitation, Lollato said. Growers are still encouraged to scout their wheat carefully since wet conditions are likely.

The weather signals suggesting a mild, wet April are quite strong, with more than 50% probability, Anderson said. This weather pattern is "favorable for rust or fungus to be active, especially with the post-dormancy phase starting as early as it did," he added.

The timing of a stripe rust outbreak will be key, Carver said.

"Many varieties dominating the Southern Plains wheat landscape in lower elevations are better equipped genetically to handle stripe rust during flowering and later stages of crop development (as opposed to now), assuming the race composition remains unchanged from last year," he said.

Other diseases to watch for in Kansas this spring are tan spot and septoria leaf blotch, Lollato added. In Oklahoma, early and plentiful presence of aphids means barley yellow dwarf will also be a threat, Carver said.

Stripe rust and other diseases are best targeted with a timely fungicide application at flag leaf emergence. However, if early scouting shows a wheat disease spreading quickly, split fungicide applications starting at the Feekes 6 (jointing) growth stage might be warranted, Lollato said.

"Diseases like stripe rust, tan spot and septoria leaf blotch develop very fast," he warned. If conditions are right, and hot spots exist in a field, they can cause economic damage in a susceptible variety very quickly, he said.

If you opt for split fungicide applications, Lollato recommends using a cheaper, generic fungicide for the first pass, because a yield response and economic return are likely to be greater from the second pass, which will protect the upper leaves.

Emily Unglesbee can be reached at emily.unglesbee@dtn.com.

Follow Emily Unglesbee on Twitter @Emily_Unglesbee.

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Emily Unglesbee