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New
Weed Control Technologies Offer Several Advantages
(Above: Dr. Michael Patterson, an Alabama
Cooperative Extension System weed scientist, discusses research on two
new weed control technologies that will soon benefit some cotton
producers.)
Auburn,
August 5, 2003
--- An
Alabama Cooperative Extension System weed scientist believes two new
weed control technologies merit a closer look by cotton producers.
One of the new
technologies, Envoke, developed by Syngenta, is a conventional
herbicide that can be applied at extremely low rates.
“It’s not a
genetically engineered product like Roundup Ready or Liberty Link but
a true chemical-discovery herbicide that can be used at only one-tenth
of an ounce per acre. That’s roughly a teaspoon of material per
acre,” said Dr. Mike Patterson, an Alabama Cooperative Extension
System weed scientist.
Patterson
presented his findings on new weed control technologies at the Alabama
Cotton Field Day, held July 31 at the Tennessee Valley Research and
Extension Center in Belle Mina.
A foliar-applied
herbicide, Envoke also has some residual activity. It is effective on
morning glory, sicklepod, pigweed and several other weeds.
“I’ve seen it kill
good-sized morning glory and sicklepod between six and eight inches
high,” Patterson observed. “It also has significant nutsedge
activity.”
Envoke can be
sprayed over the top of both conventional and transgenic crops. On
the other hand, one limitation associated with Envoke is that the
chemical can be applied only after the cotton has reached the fifth
true leaf.
“You can’t go
early with it, which is a bit of a disappointment,” he stressed.
“”That means if you’re growing a conventional variety, you’re going to
have to use some other product to get your product to the fifth leaf
stage before you can use Envoke.”
Liberty Link
cotton is another technology Patterson believes shows great promise.
Like its
competitor, Roundup Ready cotton, Liberty Link is a genetic technology
that will require growers to buy Liberty Link cotton in order to use
the herbicide product.
“Liberty Link
(herbicide) kills both Roundup Ready and conventional cotton, so
growers who use it should make sure it is applied only to Liberty Link
cotton, just as Roundup should be used only with Roundup Ready
cotton.”
As a post-emergent
herbicide, Liberty Link is similar to Roundup. It is a broad-spectrum
product that kills broadleaves as well as grasses.
“It may even work
a little bit faster than Roundup,” Patterson said. “One added
advantage is that Liberty Link cotton may have more tolerance at a
later stage to herbicide applications.”
“Roundup Ready, as
most growers know, is limited to the fifth leaf stage. After that,
you can’t spray over the top without risking a yield reduction.
Liberty Link, on the other hand, is tolerant up to the bloom stage --
a valuable tool if you are dealing with escaped weeds.”
One added
advantage associated with Liberty Link is that it appears to be
stronger on morning glory, though it appears to be weak on large
annual grasses and pigweed.
Liberty may also
help some producers obtain better control of herbicide-resistant
weeds, especially in North Alabama’s Tennessee Valley where growers
are dealing with Roundup-resistant horseweed.
Bayer, the product
manufacturer, also hopes to be granted a label permitting its use in
burn down prior to no-till planting, Patterson said.
(Source: Dr. Michael Patterson, Extension Weed Scientist,
334-844-5492.)
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