January 28, 2014
WHAT TO EXPECT
When choosing a spring application, growers should expect a residual herbicide to deliver several weeks of weed control, cover a broad spectrum of weeds, aid in resistance management and allow for crop rotation flexibility.
LENGTH OF RESIDUAL
The length of residual varies by weed, soil texture, soil pH, organic matter present, rainfall and herbicide rate. According to Dr. Christy Sprague, weed scientist at Michigan State University, “A herbicide should ideally last at least four weeks to be deemed a residual.” Valor® Herbicide, the top-selling preemergence herbicide, delivers just that.
“Valor has shown excellent length of control in the field,” said John Pawlak, product development manager for Valent U.S.A. Corporation. “Even in wet weather conditions last spring, many growers still had 4 to 6 weeks of residual weed control.”
BROAD SPECTRUM WEED CONTROL
Because weed control is the primary reason for using any herbicide, it is imperative that growers look for a residual to control those weeds that are problematic in their specific geographic location.
In North Dakota and Minnesota, for example, the number of counties with glyphosate-resistant common ragweed and waterhemp has increased almost 80% since 2008, according to North Dakota State University Extension Service reports.
In northwest Iowa, waterhemp and lambsquarters continue to be the key weeds that hinder growers.