That’s in modern times. In ancient times winnowing was a far different task. No doubt they had their eye on the problem. check this site ~ http://www.rightdiagnosis.com/medical/virgin_s_bower_poisoning.htm ~ we are probably talking about the same thing.
I am finding conflicting claims that the greek zizania, or zewan, is not the same as the bearded darnel. Maybe there is ‘grant’ money available to research this plant???? (Just kidding.)