Corn and soybean farmers might as well be soldiers locked in an ever-escalating war against the weeds that threaten their crops. New weapons — herbicides — only work for so long before the enemy retaliates by developing resistance and refusing to die. So farmers attack with new herbicides or new mixtures of existing herbicides until the cycle starts again. This has been the case for decades for two familiar enemies, waterhemp and its aggressive cousin, Palmer amaranth.
A new study co-authored by University of Illinois weed scientist Patrick Tranel shows that Palmer amaranth populations…