A new report by Dr Charles Benbrook, director of the Northwest Science and Environmental Policy Centre, Idaho, shows that contrary to claims that GM crops substantially reduce pesticide use, evidence shows that in the US the 555m acres of GM corn, soybeans and cotton planted since 1996 has increased pesticide use. Many farmers have had to spray more herbicides on GM crops in order to keep up with shifts in weeds toward tougher-to-control species, coupled with the emergence of genetic resistance in certain weed populations. For years scientists have warned of the possible emergence of 'super-weeds', Benbrook's study gives hard evidence to these claims.