Scientists said on Friday they have confirmed expanding weed resistance to a key ingredient in Monsanto's (MON.N)widely used Roundup herbicide, a troubling development for farmers and fresh fodder for Monsanto critics.
Kansas State University said scientists had found five kochia weed populations in western Kansas that have been confirmed to have become resistant to glyphosate.
Kochia, also called fireweed, is a drought-tolerant weed commonly found on land in the western United States and Canada where crops are grown and cattle are grazed.
"This complicates and may increase control costs for those growers who may have a resistance problem, but there are other herbicides," said Kansas State weed scientist Phil Stahlman.
Stahlman and other university researchers are recommending farmers use other herbicides to try to control the weeds.