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Back when generic glyphosate
was bumping around $25 per gallon a couple years ago, searching for
alternatives was smart economics.
That’s what brothers Shawn
and Jeff Adam of Batavia, Iowa, who farm with their father, Nick, did by going
with a preemergence and postemergence herbicide combination on corn. This was
before the glyphosate price crash of 2010, in which generic glyphosate is
selling for as little as $7 per gallon.
So what do they do now?
Well, a postemergence
glyphosate program would save them money right now.
Long term, though, this
strategy could cost them money in lost yields and time.
“Cheap glyphosate has not
really changed the way we do business,” says Shawn. “The way I look at it, it’s
a time-management issue.” Going with a conventional herbicide strategy
featuring both preemergence and postemergence herbicides helps them manage time
and workload during a busy planting season, he notes.
“There’s a guarantee on weed
control, and the company stands behind the product,” he adds.
Lack of residual with glyphosate
can also lead to yield-clipping early weed growth.
“A guy can spray two or
three passes of glyphosate and come in under the money on chemical costs. But
if we see any weed pressure early on, yields can be decimated. For us, it’s all
about making bushels, trying to squeeze every bushel we can out of every acre,”
Overreliance on glyphosate
has led to an increasing number of resistant weeds. “There are also cases of
weeds like morningglory, velvetleaf, and lambsquarters that aren’t resistant
but are not controlled as easily by glyphosate as they used to be across the
Midwest,” says Damon Palmer, Dow
AgroSciences Herbicide Tolerant Trait commercialization leader.
Mixing Up Action Modes
On corn, the Adam brothers
split their weed control program. On about 30 to 35% of their corn acres, they
apply a single pass of Corvus, a preemergence residual herbicide. They apply
Capreno early postemergence residual herbicide on the remainder of their corn
“We have really good luck
with it,” says Shawn. “This year, we have had some of the cleanest corn we’ve
Time management drives these
programs. Although the early preemergence program nixes early weeds that zap
yield potential, it also ties up planting time. They say the early postemergence
application of Capreno enables them to plant and still protect young corn from
About 70% of their acres are corn, with the balance planted
to soybeans. Normally, corn is a more lucrative crop. They have a postemergence
glyphosate soybean strategy, but that may change.
“The reason we haven’t gone
with a preemergence on beans is that we often don’t know if we’ll go with corn
or soybeans in the spring,” says Shawn. If they apply a preemergence with
lengthy residual on a field destined for soybeans, they lock themselves out of
corn. That may change since they are eyeing fall or early spring preemergence
products like Autumn that ease carryover concerns.
strategy also can help prevent glyphosate-resistant weeds from developing.
“Even when we have included glyphosate in a (corn) program, we’ve always had a
conventional corn herbicide in it,” says Shawn.
One drawback with growing
corn back-to-back is volunteer corn. However, this hasn’t been a problem for
the Adam brothers. One factor that halts volunteer corn is a properly adjusted
“I am a micromanager in the
combine, and we adjust combines where we try not to leave any kernels behind,”
Ditto for timely planting.
The Adam brothers planted all corn and soybeans during a time frame from April
13 to 21 in 2010. This helped get the crop off to an early start and nix weeds
due to competition and early canopy formation.
“Frost is a consideration
for soybeans, but most of the time, it doesn’t occur,” says Shawn. “Had we not
planted beans then, we would have had delayed planting. In some cases, rain
pushed back planting around here to July 4.”
www.difficultweeds.com for more on glyphosate resistance and improved