> All genetically modified crops harm the natural world and human health, in large part because they (by definition) invite and encourage the spraying of toxic pesticides

That is a flagrant abuse of the phrase "by definition"! Who is Vallianatos and on what basis does he make these claims? I looked him up and found that he has a BA in zoology and a doctorate in history, so I'd be keen to look at original sources rather than treat him as an expert.