No-Till Farmer carries an article discussing the problems, and solutions, associated with glyphosate-resistant weeds in crops established by no-till. For no-tillers to continue farming in a sustainable manner, they must diversify their weed-control programs and reduce their reliance on post-emergence applications of glyphosate, Southern Illinois University weed specialist Bryan Young says.
Since the mid-1990s, at least 21 varieties of glyphosate-resistant weeds have been identified in the U.S. Problems began to appear [from 2000], especially in no-till acres with glyphosate-resistant marestail (horseweed), Young says. Between 2005 and 2010, the resistance problem mushroomed, with some Midwestern states reporting millions of acres of glyphosate-resistant weeds, mostly marestail and waterhemp.
No-tillers who currently aren’t experiencing glyphosate resistance should not be lulled into a false sense of security. Though some farmers may answer that they’re using full rates of glyphosate to get a consistent killing of weeds, an overreliance on it — even at full rates — can still bring resistance, Young says. And spraying the weeds when they’re small won’t guarantee against resistance, either.
The acronym D.I.R.T. describes the outlook needed for no-tillers to achieve better weed control, says Young.
Diversify: Growers are advised to Diversify their weed-management tactics,
Integrate: Integrate at least two effective modes of control, rather than just relying on a single control measure such as glyphosate, to fix a problem,
Rates: Utilise full rates to improve the consistency of control for residual and foliar herbicides, and
Timing: Apply residual herbicides close to the peak emergence period for problematic weeds.
Read the full article here.
