Roundup-Ready Horseweed

A genetic mutation in horseweed (aka fleabane and marestail) has made it resistant to the exceedingly popular herbicide glyphosate (better known by the brand name, Roundup), which is widely used to control weeds in plantings of so-called 'Roudup-ready' crops, including soybeans, corn and canola. The spraying allows farmers not to plow fields, thereby conserving topsoil and keeping carbon in the ground. With the advent of resistant weeds, however, farmers are starting to plow again and/or turn to more toxic chemicals. NPR reports.