[Fhb-update_cgp] FHB Update from OK, 05/16/19

[FHB Update - Central GP, Hard Winter Wheat]

I started this past week on Monday (13-May) at the variety trial at
Chickasha, OK, where wheat was mostly full kernel watery to milky. Stripe
rust was the most prevalent foliar disease, but overall was not extremely
heavy in the variety trial. Septoria/Stagonospora was a close second to
stripe rust, and actually was more widespread than stripe rust but for the
most part was only on the lower and mid leaves. Leaf rust also was present,
but overall seemed less than stripe rust. From Chickasha, I moved to Tipton,
OK in southwestern OK where the wheat was mostly about soft dough. Leaves
here were quickly turning and showed a combination of stripe rust, leaf
rust, and Septoria/Stagonospora. However, varieties and lines with good
resistance stood out. On Tuesday (14-May), I was at the field day near El
Reno in central OK (25 miles west and a bit south of OKC). Wheat here was at
the end of flowering to full kernel-watery. Overall diseases were light with
Septoria/Stagonospora on lower and mid leaves and some stripe and leaf rust
on upper leaves. Powdery mildew also was present, but mostly only on certain
varieties. Next, a demonstration was visited near Minco, OK (about 20 miles
west). This demo was planted quite late (early December), and was mostly at
flowering. The foliar disease situation was basically the same, that is,
some stripe and leaf rust along with some powdery mildew and
Septoria/Stagonospora.

>From Minco, I moved north to the variety trial at Kingfisher, OK (30 miles
NW of OKC). The explosion of leaf rust at Kingfisher was impressive, and
finally fit with my expectations for the occurrence of leaf rust this year. 

Finally, there may be some additional diseases to watch for this year given
the extended cool and wet spring. This includes several diseases, but
primarily bacterial streak (black chaff) and Fusarium head blight (head
scab). Dr. John Fenderson (Technical Product Manager; Bayer Crop
Science-WestBred) indicated on 9-May that he observed major infections of
bacterial streak across central Texas. Dr. Brett Carver (OSU Wheat Breeder)
also indicated seeing symptoms consistent with bacterial streak at the field
day near Okmulgee in eastern OK earlier this week. Symptoms of bacterial
streak are somewhat similar to Septoria/Stagonospora, and could be
overlooked if both are present. However, the head symptoms should be more
discernable, and currently I have not seen symptoms such as this across
central and western OK.

Fusarium head blight typically occurs in eastern/northeastern OK every year,
and this spring has been favorable for this disease. Wheat heads will be
totally or partially bleached and contain shriveled and often pinkish or
salmon colored seed. To get more information on head scab, see OSU PSS-2145
(Fusarium Head Blight (Head Scab) of Wheat: Questions and Answers –
available at
http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-6307/PSS-2145web2013.pdf)
and OSU PSS-2136 (Considerations when Rotating Wheat behind Corn –
available at
http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-5436/PSS-2136.pdf).
Another outstanding resource regarding Fusarium head blight is the
“Fusarium Head Blight Prediction Center” at
http://www.wheatscab.psu.edu/. At this site there are resources describing
the disease as well an assessment tool that can be used to help predict when
spraying is critical to help prevent Fusarium head blight. 


--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