- WEED CONTROL -
Missouri farmer says pre-emergence herbicide
– a new combination of two active
In West Alton, Mo., David Bonderer sees a return to using pre-emergence herbicides in soybeans. He sees it on his 2,500-acre farm, as well as on his neighbors’ operations, which he services through his family’s dealership, Saale Farm and Grain.
“Many growers will apply a pre-emergence on early beans,” Bonderer says. “It holds weeds down, and maybe lets us plant a little earlier. Controlling those weeds also helps us in terms of insect control. And it’s going to buy us some time to make that glyphosate application a little closer to canopy so we can get by with just one [application].
“You’re going to spend the money one way or another,” Bonderer notes. “Glyphosate will cost you $4 per acre plus the application cost, so you’re looking at $8 for a second glyphosate or $12 for a pre-emerge. So a pre-emerge is going to be a little more expensive, but hopefully you’ll plant your beans a little sooner and you’ll be going into a clean seedbed.”
Bonderer tried Prefix last year, a new combination of S-metolachlor (the active ingredient in Dual Magnum) and fomesafen (the active ingredient in Reflex). He says a stale-seedbed combination of Prefix and Touchdown did a better job on large-seeded broadleaf weeds like cocklebur and giant ragweed than other pre-emergence herbicides he’s used.
“And we got better grass control than most,” he adds. A single postemergence application of Touchdown took Bond-erer’s beans, planted on 15-inch spacing, through canopy and into harvest.
Like most weed scientists, and many farmers, Young is concerned about glyphosate-resistant waterhemp. He advocates the use of at least two modes of action on waterhemp populations. Young says Prefix shows strong promise in the fight against glyphosate-resistant waterhemp.
“Prefix is one of the few herbicides that combines two different modes of action for waterhemp in one product,” he notes. “Both S-metolachlor and fomesafen have significant amounts of waterhemp activity. With the two modes of action in Canopy XL, sulfentrazone did all the waterhemp control there – it was never the ALS herbicide. In Gangster and Gauntlet, they both contain one waterhemp herbicide with another herbicide for small-seeded broadleaf weeds.”
“In most cases, we’ll be following Prefix with an application of glyphosate,” Young points out. “Three modes of action for waterhemp control in any given year is a pretty good effort.”
‘Not the weed-killing industry’
“It’s called the crop protection industry, not the weed-killing industry,” he points out. “We’re not using these products to kill weeds; we’re using them to protect our investment. That should dictate the timing and choice of the herbicide.”
By that model, a pre-emergence herbicide is a wise approach indeed.
Gibbs and Soell, who represents Syngenta, provided information
for this article.