Pigweed Leaves No Room for Error

07:00AM May 02, 2019
( Sonja Begemann )

As you peer into corn and soybean fields across the Corn Belt and Mid-South you’re hopefully seeing crop seedlings poke through soil. However, delayed planting could mean weeds, rather than crops, are poking through—and it’s time to gain control.

When it comes to broadleaf weed pests the amaranth, pigweed, family is one for which farmers need quick control. Once it hits 4” tall it’s difficult to kill—not to mention it’s shown resistance to more than five different herbicide groups.

Amaranth includes palmer amaranth, waterhemp and lesser known relatives such as red root pigweed. The commonality between these plants? They’re each prolific seed producers: unchallenged some can even produce nearly one million seeds from a single plant. Some species can even grow up to 3” a day.

“Our goal is to hold the line against pigweed and avoid large-scale infestations,” said Mark Loux, of The Ohio State University in a recent Weed Science Society of America (WSSA) news release. “We want growers to understand they can’t beat these weeds with herbicides alone.”

To carry that message, WSSA is launching the “No Pigweed Left Behind” campaign, starting in Ohio in partnership with the United Soybean Board and the Ohio Soybean Council. The new program teaches farmers how to fight back against this inexhaustible weed.

So, what are these best practices? The Ohio State University recommends the follow six tips:

  1. ID pigweed-study up on the many different species to differentiate between them and know what methods of control are available.
  2. Avoid cross contamination- don’t move pigweed seed from one field to another and be mindful of where you purchased used equipment from. Inspect machines before use.
  3. Scout- monitor fields for the pest to check for any weeds that might have escaped or have resistance to herbicides.
  4. Pick the right herbicide-use residuals to control early-emerging pigweed and mix multiple, effective sites of action.
  5. Don’t spread seed- if you run through patches of weed seed during harvest, the combine will disburse that seed. Instead, go around or chop the pigweed patches.
  6. Remove the weed safely- if pigweed plants aren’t yet producing mature seeds, cut or pull them just below the soil line. Plants with mature seeds should be bagged before removal—burn or bury under at least one food of compost.