Pigweed Persists As Arkansas Farmers Seek Answers
PIGGOTT, ARK.
Strong cotton prices are a carrot for producers
who are spending more, but gaining
ground, on one of their toughest foes: herbicide-
resistant pigweed.
The economic impact of herbicide-resistant
pigweed is different for every field and crop.
Most farmers indicate they are spending $30
more per acre on weed control in soybeans, of
which there more than 3 million acres in
Arkansas. Cotton growers are spending an average
of $75 more per acre in a year where farmers
are expected to harvest 640,000 acres,
according to the National Agricultural Statistics
Service. These dollar figures don’t include hits
from increased harvesting costs or reduced
yields.
Here’s one measure of how economically important
the pigweed problem is. When Extension
Weed Scientist Ken Smith was asked what
weed situations would be shown at the Eastern
Clay County Field Day demonstrations, he said:
“I don’t have but one situation in my life now.
We were talking about managing pigweed and
soil seed banks.”
Smith has a dual extension and research appointment
for the University of Arkansas Division
of Agriculture.
The effectiveness of new pigweed control techniques
in corn, cotton and soybeans were displayed
at the 2011 Eastern Clay County Field
Day, held July 27 at the Henderson, Palmer and
Cagle farms. About 75 producers and other
farm industry workers attended the field day,
“and they came to learn.”
Fields such as the ones shown at the field day
are living laboratories, testing theories developed
by Smith and others, to combat herbicideresistant
weeds. These weeds are fast-moving
targets, and that puts pressure on researchers
such as Smith to find new control methods
quickly and be right the first time.
“Back when I started with Extension, our role
was to wait until the researchers get three years
of data and summarize and give us the data to
pass on to producers,” Smith said.
Like other businesses that have to adapt to
rapidly changing conditions, farmers want justin-
time answers ASAP.
Years ago, farmers would’ve been upset if you
changed a recommended practice. “Today, the
farmer does want answers now, and we might
have to come back and change a recommendation
in six months or a year.”
What’s working now in pigweed management
is a three-step approach:
• Start clean.
• Use overlapping residual herbicides.
• Manage the soil seed bank.
Because the pigweeds can produce millions of
seeds per acre, and because there are no chemical
controls after reaching a certain maturity
level, it’s important to keep the seeds from forming,
if possible.
“They’re spending a lot of money taking the
weeds out of the crops,” said Smith said.
“One guy told me, ‘I had a budget this year
when I went into this. I was going to spend
$50,000 on hand-hoeing,’” he said. “‘I’ve already
gone over that. I can’t quit now. I’m not going to
quit now.’
“Fortunately, producers are making this effort
when cotton and bean prices are up,” Smith
said. “If prices go back down, they cannot spend
the levels for weed control that they are now.
But by doing what they’re doing now, by the
time the prices go back down, we hope they’ll be
able to back off the expenses a little bit.”
A fact sheet, “Prevention and control of
glyphosate-resistant pigweed in soybean and
cotton,” FSA2152, is available online at:
www.uaex.edu/Other_Areas/publications/PDF/FSA-2152.pdf. Δ