[Fhb-update_cgp] FHB Update from OK, 05/08/15

[FHB Update - Central GP, Hard Winter Wheat]

In addition to looking at wheat around Stillwater this past week, I also was
at field meetings near Kingfisher (30 miles northwest of OKC), Kildare (10
miles north of Ponca City), and Lahoma (10 miles west of Enid). Wheat was at
full berry to borderline milk.
 Stripe rust, leaf rust, and powdery mildew were present at all locations,
with stripe rust by far the most prevalent. Where a fungicide had been
sprayed (e.g., in Dr. Jeff Edwards variety trial), the effect was striking
in terms of green leaf tissue. Difference in variety susceptibility to
stripe rust was obvious, with Ruby Lee, Garrision, Pete, and Everest being
some of the more common highly susceptible varieties. There also seems to be
varieties with high levels of resistance (e.g., Gallagher, Jackpot, etc),
and intermediate resistance; however, I’ll wait until I have all ratings
in to evaluate this in more detail.
 Leaf rust can be found in some varieties at severe levels, but has not
increased to a level comparable to stripe rust. Most commonly, I am seeing
it on leaves of varieties that are resistant to stripe rust, but susceptible
to leaf rust (e.g., Jackpot).
 Barley yellow dwarf also was observed at all locations, but little to no
stunting was associated with the BYD, so infection most likely occurred in
the spring.
 Powdery mildew also was observed at every location, but only rarely was on
the flag leaf or heads.
 I have not seen any Fusarium head blight, but have had a few reports of it
from eastern/northeastern OK.
 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) 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