When Good Biological Controls Go Bad

Continuing a study that spans over a decade, Svata Louda and Charles O'Brien are releasing new information about the impact of the introduction of Eurasian weevils as a biocontrol for the invasive Canada thistle (Cirsium arvense, incidentally not native to Canada!) in the U.S. This sanctioned introduction has gone on to be the best known case against biological controls; the weevils have moved on to native thistles, some of them rare. Organizations like CABI Bioscience have since become a lot more cautious about approving new species introductions to combat invasives.