[Fhb-update_cgp] FHB Update from OK, 05/22/15

[FHB Update - Central GP, Hard Winter Wheat]

This past week I spent around Stillwater. Wheat here is mostly at mid-dough
but quickly turning. Some wheat has started to lodge with the wet weather
and wind. Head discoloration is becoming more common, with the likely causes
related to Septoria/Stagonospora and/or black chaff. Leaves are pretty much
gone due to a combination of many diseases. One set of leaf samples I
isolated from revealed stripe rust pustules, pycnidia of
septoria/stagonospora, spot blotch and tan spot. Lines or varieties that
have stripe rust resistance typically show either leaf rust pustules or more
green leaf if they also are resistant to leaf rust.

A producer in southwestern OK (Granite) indicated to me this past week that
there is abundant head discoloration and wheat is lodging. Aaron Henson
(Tillman County Ag Educator; south-central OK) told me this morning that if
the weather turned dry and warm, he would guess wheat harvest would start
within 5 days or so. He also has seen fields where wheat is lodging. Mark
Gregory (SW OK Area Extn Agron Spec) indicated much the same for the SW
district. In the panhandle, Mindy Hittle McNair (Texas County Ag Educator)
indicated they have been cloudy and wet all week, wheat varies from
flowering to soft dough, and that rust across the area is evident. This was
confirmed by Dr. Bret Carver (OSU Wheat Breeder), who just returned from the
panhandle yesterday. He indicated wheat at the Goodwell Station was mostly
around the milk stage, and stripe rust was the most prevalent foliar disease
but leaf rust was on the increase. He also indicated head discoloration and
bacterial-like symptoms. Currently we are running samples from last week to
confirm bacteria. Please see a Disease Advisory sent out in 2007 for a
complete description of causes of head discoloration
(http://entoplp.okstate.edu/pddl/pddl/2007/PDIA6-17.pdf). Dr. Jeff Edwards
and I will be in the panhandle next Tuesday and Wednesday for field days, so
I’ll have more to report on wheat in northwestern OK and the panhandle
then.

Finally, the diagnostic lab continued to receive samples testing positive
for Wheat streak mosaic virus, with several also testing positive for High
plains virus (Wheat mosaic virus) and/or Barley yellow dwarf virus. For
information on mite-transmitted diseases, I refer you to EPP-7328 (Wheat
Streak Mosaic, High Plains Disease, and Triticum Mosaic: Three Virus
Diseases of Wheat in Oklahoma) also available at http://osufacts.okstate.edu


--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 http://www.scabusa.org