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Will the wheat crop make it this year?
By Justin Petrosino, ANR Extension Educator
OSU Extension, Darke County
After last year’s wheat crop many growers are wondering if this crop
will do any better. The crop this year was planted on time thanks to
last year’s early harvest, but suffered through dry conditions. This
winter seemed very harsh and spring doesn’t seem to be going any easier
on the wheat. Thankfully over the winter we had good snow cover and
wheat is a very resilient crop.
In early winter wheat goes into a period of dormancy where metabolic
processes are decreased, water content of leaves is decreased, and the
plants ability to survive freezing temperatures increases. The growing
point of wheat during dormancy and tillering is safely protected below
the soil surface. It takes temperatures as low as -9 to -11 F to kill
the growing point of wheat. A stress that may cause some losses
this spring is ponding. If there is standing water in the field that
persists for more than a few days anoxic conditions and root diseases
like Pythium may take a toll. Unfortunately by now our seed treatments
have worn off and there are no fungicides labeled for such a condition
with Pythium. Thankfully any losses caused by these conditions
typically don’t warrant abandoning the crop because they only affect a
small portion of the field.
After we ride out the next few weeks of rain and changing temperatures
wheat management becomes all about timing. The majority of our wheat
receives a spring top dress of nitrogen. We have a broad window between
March 1 and April 30 to get nitrogen to the wheat. To maximize the
efficacy of a nitrogen application, try to avoid applying right before
major rainfall events where runoff and ponding occur. Only about a half
inch of rainfall is needed to incorporate broadcast N. The problem here
is finding a weather forecast accurate enough to base a decision.
Herbicides and fungicides can be effective management tools if they are
needed. A spring application of a growth regulator like 2,4-D can
provide cheap, effective control of most broadleaf weeds, including
marestail if you haven’t frost seeded clover. Application costs can be
decreased by applying the herbicide with the N application. However,
growth regulators need to be applied before wheat begins jointing,
usually by mid April. For more information on spring weed control in
wheat you can pick up a copy of the 2011 Weed Control Guide here at the
Extension Office or you can view the guide online at
http://ohioline.osu.edu/b789/index.html.
Of all the management tools, timing is most critical for fungicides.
Just a reminder fungicides are needed when we have a susceptible
variety, a disease organisms present, and weather conditions are right
for growth. On-farm research by Dr. Pierce Paul, our state wheat
pathologist, and many others in the academic community, shows that if
disease conditions are right, a fungicide application between Feekes 8
and 10 growth stage will protect the flag leaf and return more dollars
than green-up and split applications. Protecting the flag leaf helps
prevent losses from diseases like Stagonospora and powdery mildew. For
head scab effective fungicides need to be applied when wheat is
flowering. Because this is a very narrow window and our best fungicides
have limited control of scab relying on varietal resistance is probably
our best management tool for scab. For more information on disease
management in wheat consult the Ohio Agronomy Guide available in the
office or online at http://ohioline.osu.edu/b472/index.html, the Ohio
Corn, Soybean, Wheat Pocket Guide, or visit the Plant Pathology website
maintained by Dr. Pierce Paul at
http://www.oardc.ohio-state.edu/ohiofieldcropdisease/wheat/wheat1.htm .
Wheat is a very resilient crop. I’ve seen it survive temperature swings
from the mid 80s down to 16 F overnight followed by a week in the 20s
and 30s. With a little fertilizer, herbicide, and fungicide, if they
are needed, and a lot of luck, this year’s crop will hopefully rebound
from a slow start.
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