Glyphosate resistant giant ragweed populations have been confirmed in Indiana and Ohio. Glyphosate is the active ingredient in herbicides such as Roundup and Touchdown.

Bill Johnson, Purdue University Extension weed scientist says the glyphosate resistant giant ragweed population was found in three fields in central and southwest Ohio and one Northeast Indiana County. “The population in Indiana is located in Noble County, which is northwest of Ft. Wayne. The field in which it was located had been in soybeans six out of the last seven years, and the producer relied solely on glyphosate for giant ragweed control,” said Johnson.