Adriana Duduleanu/Getty Images Last month’s US Supreme Court ruling in favour of the makers of the weedkiller Roundup (formerly Monsanto, now owned by German pharmaceuticals group Bayer) upended thousands of lawsuits based on the cancer risk associated with the product’s active ingredient glyphosate. But the ruling also highlights a longstanding controversy about how the product’s use is approved, including in New Zealand. The US Environmental Protection Agency (EPA) has judged glyphosate “not l