ROCKFORD – Crop-menacing super weeds have developed resistance to commonly used herbicides, and experts are urging Illinois farmers to be vigilant as the tenacious plants move northward across the state.
A dozen weed types have become resistant to glyphosate, an active ingredient in commonly used farm and garden herbicides, The Rockford Register Star reported.
The weeds, which the herbicides used to be able to single out and kill, have evolved to imitate the crops around them and have become increasingly difficult to eliminate.
Two species from the pigweed family, Palmer amaranth and common waterhemp, are particularly worrisome to corn and soybean farmers. Some can grow to be seven feet tall and produce 1 million seeds.
The Palmer amaranth, which is indigenous to dry regions in the Southwest, has now been documented in northern Illinois’ Grundy County and can lead to huge corn and soybean losses.
A key strategy is for farmers to fight the weeds before they have a chance to establish themselves firmly in a field over several years, said Higgins.