FHB Update from OK, 05/01/17

The last three days of last week were spent in southwestern (Altus), central OK (Apache & Chickasha) as well as here around Stillwater. Wheat I saw at those locations ranged mostly from milk to soft dough, with some even approaching medium dough. I’m not sure about wheat in northern OK and over into the panhandle. The Panhandle is of particular interest with the far western parts of it receiving significant snow (up to 6-12 inches I heard on weather reports around Boise City).

Flag leaves on wheat across southwestern and in central OK are mostly gone as a result of rust (both stripe and leaf, but primarily leaf rust I think), wheat streak mosaic, and barley yellow dwarf. I saw little active stripe rust, but did see more active leaf rust. An abundance of leaves showed rust telia, but again, mostly leaf rust (I think). I also saw scattered white heads in wheat at Altus. Examination showed dark lower stem internodes and splitting of stems revealed cottony fungal growth in the lowest internode with a reddish/pinkish color indicating Fusarium root rot as the most likely cause. A sample of white plants with mostly sterile heads was brought to a field day at Apache, OK in central OK; examination revealed take-all as the likely cause. Barley yellow dwarf was present at all locations, but seemed more prominent at Chickasha.

As in my last update, Wheat streak mosaic virus (WSMV) continues to be found and reported across a large area of western Oklahoma. The cool wet weather will likely help manage infected plants to continue to mature, but yields definitely will be significantly impacted. For more information on mite-transmitted wheat viruses such as WSM, please see OSU Fact Sheet EPP-7328 (Wheat Streak Mosaic, High Plains Disease, and Triticum Mosaic: Three Virus Diseases of Wheat in Oklahoma) available at http://pods.dasnr.okstate.edu/docushare/dsweb/HomePage

--Bob Hunger, Extension Plant Pathologist, Oklahoma State University

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org