Recent in-field experiments have confirmed that waterhemp and giant ragweed two of the most yield-robbing weeds for Iowa producers, have become resistant to glyphosate herbicides.
Warnings about the development of glyphosate-resistant waterhemp in Iowa were publicized as early as 2000. University experts in Iowa were some of the first to discuss glyphosate-resistant weeds and their potential impact.
Growers across the nation, including those in Iowa who are now experiencing the problem first-hand, are being urged to recognize the importance and reality of resistance, develop a plan to combat the problem on their fields and in their community and, most importantly, take action now.
Iowa retailer Matt Appel has seen the negative impact of using glyphosate followed by glyphosate, and now recommends that his customers incorporate pre-emergence, residual herbicides into their weed management program to combat glyphosate resistance.