The wet spring and delayed planting have weed control specialists thinking this may be an unusual year for weed control. It may be a throwback year to the days before broad-spectrum herbicides like glyphosate and Ignite. More scouting, better timing, and more careful management, along with perhaps the addition of some other products you don't typically apply, might be needed to help obtain the type of weed control you've become used to in the glyphosate era.
Weed control specialists offering tips about this unusual season include Purdue University experts Bill Johnson, Glenn Nice and Tom Jordan. The fourth Purdue weed control specialist, Tom Bauman, also an honorary Master Farmer named a year ago, is retiring at the end of this month.
Here are tips to stay out of weed trouble this year.
Late mergers- Some of the dirty dozen introduced yesterday, including giant ragweed and nightshade, may emerge later in the season, and may emerge in multiple flushes. Neither fact is favorable for someone trying to control weeds.
Not a one –pass year- This may not be the year when you can expect to get clean fields with just one pass of glyphosate or Ignite. These are contract herbicides that only kill weeds that are up. Weeds with multiple flushes have the best chance to produce escapes that survive and mature by the end of the season this year.
Not a two- pass year- Even two passes of glyphosate or Ignite may not get some of these weeds this season, the specialists note. Part of it will depend on rain events. Individual rain events may bring up another flush of some of these troublesome weeds in certain fields.
Consider additional choices- This may be the year you need to add something besides the broad-spectrum product in your spray tank.. There's still a large choice of postemergence products labeled for most of these weeds.
Combination of choices crucial- Consider weed height, label recommendations, and other factors to get the right herbicide for the weeds in the field.
Scout late- Don't assume you're done this season when you sidedress nitrogen. If you don't go back and check and scout, which means more than driving by or walking the end rows, this could be a season when weeds take control, the specialists say. Be prepared to do some late-season scouting for weeds.
Consult weed guides- Check with your Extension agent and consult the Purdue Weed Guide before deciding exactly which products to apply.