is part of the Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

  • American Agriculturist
  • Beef Producer
  • Corn and Soybean Digest
  • Dakota Farmer
  • Delta Farm Press
  • Farm Futures
  • Farm Industry news
  • Indiana Prairie Farmer
  • Kansas Farmer
  • Michigan Farmer
  • Missouri Ruralist
  • Nebraska Farmer
  • Ohio Farmer
  • Prairie Farmer
  • Southeast Farm Press
  • Southwest Farm Press
  • The Farmer
  • Wallaces Farmer
  • Western Farm Press
  • Western Farmer Stockman
  • Wisconsin Agriculturist


Monsanto recently announced that a common ragweed in one field in central Missouri is resistant to glyphosate. Monsanto reported that it made the resistant determination with University of Missouri weed scientist Reid Smeda. According to the company, the resistant ragweed was confined to a 20-acre section of the field.

Common ragweed now joins some biotypes of marestail and ryegrass shown to be resistant to glyphosate. Monsanto points out that these resistant cases are managed with tankmixes, which is the suggested treatment for common ragweed. The company recommends tank mixing FlexStar or Phoenix herbicides with Roundup for postemergence applications in soybeans to treat resistant ragweed. Another option is Valor or Scepter for soil-applied programs. In corn, herbicides such as triazines and growth regulators may be added to the herbicide program.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.