Evaluating the extent of freeze
damage to our area wheat is still the main issue for wheat producers. Just about the time producers, crop
consultants, and advisors are ready to make a solid freeze assessment another
round of freezing weather moves in. As
of April 23, it is difficult for me to find irrigated wheat fields in the area with
no freeze damage whatsoever to the growing point or stalk. The severity of damage sustained looks highly
variable from area to area, field to field, and also across individual
fields. Areas irrigated shortly before
any one of the recent cold snaps seem to be in the worst shape. Many times ice from the recent pivot
irrigations formed on and over the plants in a sheet causing serious damage to
that area of the field. Fields already experiencing
serious drought stress had less crop canopy to ‘blanket’ the heads and growing points
and have significant freeze damage also.
Damage generally seemed more prevalent the farther north I moved across
Hale and Swisher counties. Exceptions to
this observance can be found, both better and worse, just about anywhere across
both counties. Experience does show that
we should never count wheat completely out until the heads actually
emerge. Many fields are moving into flag
and boot stages now.
Of the fields I
have looked at this week, the percent damaged heads ranges from 5% to 60%, with
most irrigated fields averaging about 15% in Hale and 25% in Swisher. This is not a 1:1 head damage to yield loss
relationship. Historically, that
relationship is more 2:1 in nature. Secondary tillers, if healthy, can help
compensate in yield and grain weight. It
remains debatable what the yield potential of the area wheat crop was before
the recent frost events occurred with so many detrimental factors working
against the crop.
If present,
freeze damage to the stalk will be much more severe in economic terms than
damage to the head or growing point. Fields
with this type of damage are very likely to lodge as the grain matures and
become un-harvestable for hay or grain. In
addition, that stalk becomes limited in the amount of grain fill it is capable
of. Symptoms of freeze damage to wheat
stalks include a brownish-red discoloration and are easily collapsed compared
to healthy green stalks. I have noted a
few low lying fields already lodged well before boot and have had several producers
report the same. In these cases, the
wheat is lost to any use other than grazing or cover.
Greenbugs and other aphids can still be
found in most area wheat fields, but appear to have run their economic course. Area insecticide treatments seem to have
worked well where applied. Many
producers opted not to treat for economic infestations of greenbugs this season
due to the already bleak wheat situation and economic outlook. In fields where greenbugs were allowed to run
their course significant pest damage has occurred, but predators and
parasitoids are now working their way through the aphid populations and look to
have the pest on the downward slope. I
urge producers and consultants to remain vigilant in their pest and plant
monitoring efforts. Each field is likely
to have unique populations and situations and the threat of economic damage
from greenbugs are still present.
On April 12,
Monti Vandiver, CEA – IPM in Bailey and Parmer counties, released his findings
confirming a few pocketed populations of chlorpyrifos resistant greenbugs
surviving 1 pt/ac. applications in those two counties. One ray of sunshine on an otherwise bleak
assessment of the current wheat situation is that several area producers opted
not to treat their greenbug problems.
This offers a chance for our likely susceptible or at least less exposed
populations of greenbugs to survive and possibly help stem the encroachment of
resistance into our area and perhaps ease the pressure on those producers
nearby.
I welcome any
thoughts or questions you may have regarding your wheat situation and I
encourage consultants to share your field observations with us too. Thanks,
Blayne
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