| BOZEMAN In the world of agriculture, the phrase more
is better isnt always a safe bet. When it comes to
killing weeds, the need to use the right amount of the right
herbicide under the right conditions is a serious issue.
Not only are consumers and agricultural producers concerned
about how weed management methods affect health, but the weeds
themselves keep coming up with new curves.
Mike Violett, a dryland wheat farmer from Chester,
encountered a form of the weed kochia that didnt seem to be
responding well to the herbicides he was using. He had heard
of herbicide resistance in weeds, so he sent a sample to A.J.
Bussan, crop weed specialist at Montana State University in
Bozeman.
Sure enough, the kochia was resistant to a handful of
herbicides, two of which Violett had been using in his
chemical fallow process.
Farmers are aware that weeds can develop resistance to
herbicides, much in the same way that bacteria can become
resistant to antibiotics, and nobody wants to see
herbicide-resistant super-weeds popping up on the
horizon. Rotating chemicals is one of the ways that growers
limit the risk of herbicide resistance.
Violett says he was glad he had the kochia specimen tested,
so that he could be more aware of how he uses a particular
herbicide, and limit the number of times it is applied. We
knew that there was the possibility of resistance, he said.
We just thought it would be something wed do for our own
benefit.
Harold Schultz, who markets and distributes herbicides,
fungicides and insecticides for UAP Northern Plains of
Billings says there is an awareness in the agricultural
community that kochia is tolerant to certain herbicides. The
weed, which seeds prolifically, thrives in agricultural land
that has been taken out of production.
Thirty years ago you could take kochia out with a
variety of herbicides that wont work today, says
Schultz. He added that the pace that the weed becomes
resistant to herbicides seems to accelerate with each
generation. Thats why its so important to practice
rotation to prevent further resistance.
Agricultural producers who grow everything from alfalfa to
sunflowers constantly battle weed infestations. Weeds rob
growers of harvest-time dollars, ruin livestock forage and can
even endanger human health. There are multitudes of herbicides
on the market and each is useful on a different spectrum of
weeds.
Each brand name has strict guidelines for its proper use,
and to complicate matters, the formulations and restrictions
for a given herbicide can change from year to year. If that
werent enough to keep a farmer or rancher guessing, the
problem of herbicide resistance is the icing on the cake.
Keeping track of all these herbicides and their effectiveness,
application methods and safety restrictions is a daunting task
for a small army of researchers, not to mention a small
farming operation. Thats why the Extension programs from
Montana State University, Utah State University and the
University of Wyoming work together to assemble a force of
weed specialists and researchers when they publish the Montana-Utah-Wyoming
Weed Management Handbook every two years.
This year, MSU Crop Weed Specialist AJ Bussan spearheaded
the effort, with expert contributions from co-editors Steven
Dewey (USU) and Tom Whitson (UW), as well as input from MSU
Extension Weed Associate Meghan Trainor. In updating the
handbook, Bussan and Trainor collaborated with 11 authors:
weed scientists, pesticides specialists, botanists and
agronomists from the three states. They also obtained the most
current information available from herbicide industry
manufacturers. The handbook combines these authors research
about the effectiveness of various herbicides on weeds found
in 14 major agricultural crops as well as on aquatic sites and
pastureland.
More than 100 herbicide trade names are covered in the
book. Under each type of agricultural site, the handbook lists
scores of different weeds, then cross-references the
effectiveness of herbicides recommended by manufacturers for
each weed. It sounds complicated, but the book is organized
with simplicity in mind, with easy-to-read tables and precise
explanations. It also contains useful information on such
indispensable topics as safe use, improved methods, properties
of herbicides, sprayer calibration, and worker protection.
The 300-page 2001-2002 Montana-Utah-Wyoming Weed
Management Handbook costs $10 and can be ordered through
your local Montana State University Extension office. MSU
Extension also stocks several weed identification guides and
other weed management resources. |