[Fhb-update_cgp] FHB Update from OK, 05/29/15

[FHB Update - Central GP, Hard Winter Wheat]

Dr. Jeff Edwards (Small Grains Extn Agronomist) and I spent Tuesday and
Wednesday in the OK panhandle at variety trial field days located near Keyes
(Cimarron County), Balko, and Hooker (both in Texas County). A significant
number of wheat fields were in a condition I have not seen before (at least
not to this extent). These fields had small islands of wheat that was at
milk (approaching soft dough) surrounded by large areas of greener tillers
that ranged from just prior to flowering to initiation of kernel formation.
This condition resulted from the drought during this past fall, winter, and
early spring, which lasted until mid-April followed by the cool and wet
weather since mid-April. Much of the wheat in these fields was shut down by
the drought but there also were isolated pockets of wheat that more or less
made it through the drought. As cool temperatures and moisture became
prominent in mid-April, the areas hit hard by drought recovered and sent up
secondary tillers that are now green and less mature than the “islands”
of wheat that made it through the drought. Hence there is 2-3 weeks
difference in maturity between different areas within the same field. In
some fields there are only a few “islands” of secondary wheat, but in
other fields the secondary wheat predominates with only “islands” of
more mature wheat. How this will play out over the next month will have a
great deal to do with the weather. Dr. Edwards feels that if cool weather
continues, the secondary tillers stand a chance of making wheat. However, if
hot (>90 F), dry and windy weather enters the picture, the secondary tillers
likely will not finish.
 As in down-state in Oklahoma, stripe rust was prevalent at all locations
with leaf rust present on varieties such as Greer and Jackpot that have
excellent stripe rust resistance but are susceptible to leaf rust.
 Damage from wheat streak mosaic (WSM) also was evident, but in the fields
where the variety trials were located incidence was low and damage minimal.
However, from samples we have continued to receive from the panhandle there
must also be fields that have been significantly impacted by WSM.
 We also visited one field (an irrigated circle) where we thought black
chaff may be involved, but this appears to be more a case of physiological
leaf spotting than bacteria. Isolation and testing are being started today.
Other samples received from north-central OK last week where black chaff is
suspected to be involved are still being evaluated. However, as indicated
last week head darkening is definitely more common down-state than it is in
the panhandle.


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

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