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 Two
New Weed Technologies Offer Convenience and Flexibility
Auburn,
Jan. 31, 2002
--- Roundup Ready technology is the 800-pound gorilla of
weed-control in cotton farming, and that’s not likely to change
anytime soon.
But a handful of
producers still insist on having their cake and eating it too. They
want effective weed control and more flexibility often associated
with conventional cotton varieties.
One expert
believes two new technologies on the horizon may provide some
producers with these advantages.
Liberty Link
cotton, manufactured by Bayer, is a transgenic variety very similar
to Roundup Ready. It’s also effective on many of the same weeds,
“though a little better or weaker” depending on the weed, says Dr.
Mike Patterson, an Alabama Cooperative Extension System weed
scientist.
On the other
hand, Liberty Link is used with the herbicide gluphosinate rather
than glyphosate associated with Roundup Ready cotton – a factor that
allows Liberty Link to tolerate more herbicide sprayings.
“With Roundup
Ready cotton, you get tolerance only up to about the fourth leaf,”
Patterson says, “and you’re not supposed to spray over the top
beyond the fifth leaf. After that, you have to go to post-directed
spraying.”
With Liberty
Link, on the other hand, you can spray up to the tenth leaf, thereby
freeing the producer of the added complication and expense
associated with post-directed spraying.”
Even
with these advantages, Liberty Link cotton is no panacea. While
Bayer is expected to wave technology fees, acre-by-acre application
rates for Liberty Link may still be more expensive than Roundup
Ready.
An
added disadvantage is that only a limited amount of seed will be
available this year, Patterson says. And since this will be divided
among the 18-cotton-producing states, each state will end up with
only a few thousand planted acres of the new cotton.
One other
product that will afford some producers with more flexibility is
known by its brand name Envoke, manufactured by Syngenta.
Unlike Liberty
Link, Envoke is a conventional herbicide that can be used on all
cotton varieties – transgenic and conventional alike.
That’s a plus for some producers, because it will enable them to
switch back to the flexibility often associated with conventional
cotton varieties. Add to that Envoke’s effectiveness on sicklepod
and morning glory, and you have what Patterson considers a winning
combination.
“Some of our conventional varieties appear to have a little better
grading quality than the transgenic varieties,” he says. “That
certainly doesn’t apply in every case, but the fact remains that
there are conventional varieties out there that are better from the
standpoint of grading and fiber quality, and that translates into a
better price.”
Envoke also works effectively at very low rates of application –
“about one-tenth of an ounce an acre, which amounts to about a half
teaspoon.”
Even so, while Envoke can take out many of the most important
broadleaf weeds, it is not effective on small-flower morning glory,
a perennial problem in southeast Alabama and southwest Georgia. An
added disadvantage is that at the rate it will be used with cotton,
it will not be as effective as Roundup Ready cotton in controlling
grasses. This means growers will have to use other herbicides at
planting for effective control.
Availability is another problem, at least for the foreseeable
future.
Envoke apparently will not be obtainable with a full label until
next fall – effectively eliminating it during the 2003 growing
season, though Patterson and other experts are lobbying for an
earlier use application for Alabama producers.
While neither of these technologies, Liberty Link and Envoke, will
replace Roundup Ready cotton, Patterson believes they ultimately
will be valuable tools for some producers looking for more
flexibility.
Also, by rotating these technologies, growers may be better equipped
to cope with the added challenge of weed resistance, a problem that
will almost certainly will arise with Roundup Ready technology.
Most
important of all, he says, is that the convenience afforded by these
chemicals will provide some producers with the means to compete more
effectively in an increasingly global farming economy.
(Dr.
Mike Patterson, Extension Weed Scientist, 334-844-5492.)
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