Farm magazines and rural, Midwestern airwaves are full of stories and advertising for the latest herbicide-based solutions for corn and soybean fields infested with multiple, herbicide-tolerant weeds.
Perhaps the most challenging is glyphosate-resistant waterhemp.
In a March 29, 2017 Farm Industry News story by Willie Vogt entitled “Taking on weed resistance”, weed management experts describe the complex challenge facing most farmers this season.
Very few effective herbicides remain to control a half-dozen weeds resistant to glyphosate (Roundup), but by far the most damaging on many farms is waterhemp.
The math facing farmers dealing with resistant waterhemp is brutal —
“If one female waterhemp survives every 100 square feet in a field that would mean about 87,120,000 seeds per acre. At 30% viability after two years that would drop to 25,136,000 plants. If you get 95% control, that still leaves more than 1.3 million escapes.”
This is why weed management experts are urging farmers to apply herbicides that work through at least two effective modes of action, both early in the season and post-emergence.
Plus, experts are urging farmers to use a range of non-herbicide control measures in an integrated system that deploys “many little hammers.” The goal is zero-waterhemp survival and zero-additions to the weed seedbank.
Willie Vogt, “Taking on weed resistance,” Farm Industry News, March 29, 2017, available at: http://www.farmindustrynews.com/crop-protection/taking-weed-resistance