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OSU
Extension Darke County
Fall Herbicide Treatments - Just
Keep on
Spraying
By Sam Custer
There
is still time this fall to apply
herbicides for control of winter annuals and marestail, and the weather
this
week makes it an ideal time to do so. Regarding the question of how
late fields
can be treated, we have applied well into December under cold
conditions and
still maintained control with effective treatments.
Mark Loux, OSU Extension, reports that
applying under cold conditions slows the rate of kill but this is not
an issue
for fall treatments anyway, since the goal is to have fields free of
weeds by
early spring. We
have had some cold
nights but no extended periods of freezing weather, and it appears to
us that
the winter weeds that are targets of fall applications are mostly green
and
healthy.
A
few other reminders:
•
There is no need to include herbicides with
residual activity at this point, since emergence of additional plants
is
largely finished for the fall. None
of
the residual herbicides except products that contain chlorimuron
(Canopy,
Cloak) provide control of weeds that emerge in the spring.
So if you were adding
metribuzin or other
residuals for control of weeds that could emerge later in fall, these
can be
omitted. Note: metribuzin
plus 2,4-D does
control most
emerged winter annuals so that is still a viable option even where
residual is
not desired.
•
We have heard a lot about the use of
2,4-D/dicamba premix products this fall, possibly due to availability
or price. This
broad-spectrum mix can be weak on a few
weeds, and dicamba has not been an especially effective cold-weather
herbicide
in our research. We
suggest the addition
of some glyphosate, metribuzin, or other herbicide to 2,4-D/dicamba
treatments,
especially for late fall applications in cold weather.
•
A reminder that fall is the most effective
time of application for control of wild carrot and poison hemlock. These are biennial weeds
and the low-growing
first-year plants present at this time are much more susceptible to
herbicides
compared with taller plants next spring.
Take advantage of this opportunity to
apply herbicide to field borders,
roadsides, fencerows, etc for control of these weeds.
We suggest using a mixture of glyphosate
plus
2,4-D and/or dicamba. Where
the goal is
not to kill grass, options include a 2,4-D/dicamba mix and Crossbow.
Results
from the 2012 Ohio Corn Performance
Test are now available on line at:
http://www.ag.ohio-state.edu/~perf/
or
http://agcrops.osu.edu/specialists/corn
The
2012 Ohio Soybean Performance Trial Results
as a printable (pdf) file of results in now available at:
http://agcrops.osu.edu/specialists/soybean/specialist-announcements/2012%20OCJ%20Report-SB%207%20pages.pdf
and the searchable sortable web page should be available next week at
http://hostedweb.cfaes.ohio-state.edu/perf/
For
more detailed information, visit the Darke
County OSU Extension web site at http://darke.osu.edu, the OSU
Extension Darke
County Facebook page or contact Sam Custer at 937.548.5215.
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