They say timing is everything. When it comes to weed control, that’s close to the truth. Timing certainly is important.
Farmers who put together a successful weed control program need to make timely herbicide applications from before planting through their postemergence applications. Retailers can help their customers make plans that allow for these timely applications.
Into the field earlier
Changes in planting dates may require changes in traditional herbicide application dates, says Shawna Hubbard, Product Manager for Corteva Agriscience™, Agriculture Division of DowDuPont.
“As we plant earlier and earlier, farmers need to adjust their herbicide applications,” Hubbard says. Any operation applying growth regulators – such as glyphosate, 2,4-D or dicamba – early in the year needs to ensure the temperatures are warm enough that weeds are actually growing. If they’re not actively growing, these herbicides will be less effective.
“We also need to get residual herbicides on before weeds can gain a foothold,” Hubbard says. “Because we’re applying residuals earlier, we may need to consider using higher rates: We’re often asking them to control weeds an extra two, three or four weeks before we apply postemergence treatments.”
Weeds dictate application timing
Timing is critical for postemergence applications as well. Hubbard suggests applicators base treatments on the size of the weeds, not the calendar.
“It’s better to go a little earlier than you traditionally would,” she says. “For instance, with Enlist One or Enlist Duo herbicides, we should be applying when weeds are no more than 4 to 6 inches tall. If you’re worried about a second flush of weeds after your postemergence application, you have a couple of solutions.”
Adding a qualified residual herbicide to your postemergence tank mix can extend protection. Qualified herbicides for tank-mixing with Enlist One™ and Enlist Duo® herbicides are listed at EnlistTankMix.com. In addition, if farmers apply postemergence herbicides a bit early, they can always come back with another round of an Enlist herbicide or glufosinate over Enlist™ cotton or Enlist soybeans.
“Don’t wait for late flushes of weeds to make your first postemergence application,” Hubbard says. “Weather could delay that application and put a lot of pressure on your residuals to hold the fort.”
Spring delays in 2018 meant some growers never got a residual down. That, in turn, required early postemergence applications. Wet field conditions meant some of these applications couldn’t be made until weeds were considerably larger than ideal for complete control.
Time to start planning
For 2019, Hubbard cites four goals that can help make a weed control program more successful:
- Start with a clean field at planting.
- Use residual herbicides that feature more than a single mode of action.
- Make timely applications of postemergence herbicides. For Enlist herbicides, this means spraying before weeds reach 4 to 6 inches.
- Add an appropriate residual herbicide to your postemergence product to extend the efficacy of this application.
Farmers who keep weeds under wraps all season long reap benefits in the fall. A weed-free field at harvest not only makes it easier to combine the crop but also limits the spread of weed seed.