Guy's newsletter: perfect patios & tainted bread

As combine harvesters rumble across Britain through fields of rape, then barley, then wheat over the coming weeks, around a third of these crops will have been treated with the herbicide glyphosate to speed harvest and aid weed control. It’s no surprise that, according to Defra, this chemical is found in 30% of UK bread. When I grew my first field of veg back in the 1980s and was still arguing with myself about whether to go organic, I spent a lot of time pulling out docks, couch grass and creeping buttercup; they would regenerate from the smallest piece of root and it seemed a never-ending battle. The traditional method of weed control was deep cultivation and surface dragging to dry them out; time and energy consuming, impossible once a crop was planted, and damaging to the soil.

In 1970 Monsanto patented glyphosate, the active ingredient of Roundup. It is absorbed through the leaves to every part of a growing plant, so it kills even the roots. At university I was taught it had virtually zero mammalian toxicity and was environmentally benign, but this was too good to be true; the World Health Organisation has recently classified glyphosate as a “probable carcinogen”.

Glyphosate has grown to be the world’s favourite herbicide for farmers and gardeners alike, with sales growing 400% in the last 20 years alone. The patent lapsed in 2000 but by then Monsanto had moved onto GM crops, most of which were modified to withstand glyphosate, which is sold in combination with the seed. At Riverford we learned to control most weeds through crop rotation but I have always found the argument that glyphosate reduces soil cultivation and therefore protects soil flora and fauna, and reduces erosion and fuel use, at least potentially persuasive. Set these benefits against its implication as a carcinogen, endocrine disrupter and cause of birth defects, and it rather loses its edge.

Monsanto and the agrochemical lobby is furious and are accusing the WHO of being selective in the choice of studies it has based its conclusions on; a bit rich considering the agrochemical industry’s history in selective use of data. Given the money involved this will be a long and dirty fight reminiscent of the battle the tobacco industry put up, but my bet is that glyphosate will be banned within ten years. Tell your friends and family, they will probably thank you for it.

Guy Watson