A wet spring has created a favorable environment for wheat disease for much of Oklahoma and Texas production areas.
Bob Hunger, Oklahoma State University Extension wheat pathologist, offered a wheat disease update in a recent blog and touched base with small grains specialists in Texas.
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Here’s a brief look at what Extension specialists are seeing as the crop nears harvest.
Hunger says wheat around Stillwater is at milk to soft dough, with wheat in northern Oklahoma more in the full kernel to milk stage. He recently checked wheat near Stillwater, Lahoma and Alva. “On susceptible varieties that were not sprayed, the effects of stripe rust were striking,” he says. “Although only a little active sporulation of the stripe rust fungus can be seen at Stillwater, quite active sporulation was apparent at Lahoma. Stripe rust also was found at Alva, but at a much lower incidence.”
He adds that wheat streak mosaic (WSM) is more common this year across northern and northwestern Oklahoma. “(Last) week I again visited an area where several fields of commercial wheat were significantly impacted by an adjacent field in which volunteer wheat and/or weeds were not controlled following the 2015 harvest. This situation can result in devastation of wheat in surrounding fields.”
He says the OSU Plant Disease and Insect Diagnostic Lab is receiving samples testing positive for the presence of the viruses that cause WSM, high plains disease, and barley yellow dwarf. He recommends Fact Sheet EPP-7328 (Wheat Streak Mosaic, High Plains Disease, and Triticum Mosaic: Three Virus Diseases of Wheat in Oklahoma) for more information.
In Texas, Clark Neely, Texas AgriLife Extension small grains and oilseed specialist) reports recent stripe rust activity. “I was in wheat plots (recently) in Concho County. There was still active stripe rust in the trial (hard red winter wheat varieties WB 4458 and Bentley). Most varieties were in the soft dough stage. Leaf rust was active as well at light to moderate infection rates.
“Active leaf rust was also present at moderate levels in Hill and Williamson Counties last week, though stripe rust had mostly faded and produced teliospores at that time. They were at soft dough at the time.”
Neely says harvest has begun in South Texas plots and many producer fields are approaching harvest in the Central Texas region, likely in the next one to two weeks.”
Also in Texas, Extension integrated pest management specialist Xandra Morris reports identification of stem rust in early May in a Hill County field. She says the variety infected was TV8861 (a soft red winter wheat from Terral). “Rust was found in a local producer’s field. Wheat ranged from soft to hard dough. We have had much more rain that normal. The rust doesn’t seem to be severe.”