Four Weeds to Remember for PEST Week, June 22-26

Waterhemp ( Sonja Begemann )

This week, Take Action by the United Soybean Board (USB) is launching PEST Week—Pest Elimination Strategies and Tactics. Throughout the week, experts from universities and the industry will provide farmers with more information about how to breakdown the pesticide-resistance challenge into manageable steps.

“PEST Week is really a reminder to invest in best management practices now to protect our yields, so we don’t pay for it later at the elevator,” said Tom Oswald, USB farmer-leader from Cleghorn, Iowa in a recent press release. “After a tough spring, it’s more important than ever to take this seriously.”

To kick off the week, experts with Take Action outlined four of the most problematic weeds corn and soybean farmers face each year.

  1. Waterhemp-can grow more than one inch daily and can be difficult to control with herbicides, if it exceeds six inches. It’s a high-volume seed producer. Seeds can be carried by the wind, water and a variety of other vehicles.
  2. Palmer Amaranth-similar to waterhemp, it’s also a prolific seed producer at 250,000 to 500,000 seeds per plant. It can germinate throughout the growing season which means farmers need to scout all season.
  3. Giant Ragweed-a large-seeded broadleaf that can be troubling in the early season for corn and soybeans. Plan a good, effective pre-emergent herbicide application with a different post-emergent site of action.
  4. Horseweed-also known as marestail, emerges late market through June, or late summer into fall. It can produce up to 200,000 seeds per plant that can travel by wind. Look back at field history to know if you should prepare for this weed.

Scout throughout the season to check for escapes and determine if it was application error or if you have new resistance in fields. If it’s an application error, it’s likely you’ll see a variety of weeds emerging. However, if you see just one species it’s possible you have herbicide resistant plants in your field.