Four students from the University of Guelph have been named the “Best Student Weed Scientists in North America.” They won the gold medal at the 2011 Weed Olympics held in Knoxville, Tenn. earlier this summer, beating out 17 other schools, according to the university. Among other tests of their skills, the Ontario Agricultural College (OAC) students had to identify over 100 weed species and discern an herbicide from a list of 30. Guelph was the only Canadian school to compete.