Herbicide resistance

After 20 years of heavy use of herbicides such as Roundup, surprise! evolution! and the weeds have become so resistant that the herbicide is useless.

(I originally came across this story in the New York Times, but since they will soon be putting their stories behind a pay wall, I will no longer link to their articles. While they sit overestimating their own importance, the rest of the world will just move on.)

http://en.wikipedia.org/wiki/Roundup