Feelings run strong out here when it comes to gardening. I am a big fan of Phosphorus Soap (ie: glyphosate or Roundup) for weed control. Other people think that it oozes from Satan's pustules.
Matt Ridley has a great post on the subject - he owns and manages a large estate in England and knows what he is talking about:
GLYPHOSATE, THE MMR VACCINE AND PSEUDOSCIENCE
Uncovering the subversion of scientific methods in pursuit of politics
Science, humanity’s greatest intellectual achievement, has always been vulnerable to infection by pseudoscience, which pretends to use the methods of science, but actually subverts them in pursuit of an obsession. Instead of evidence-based policymaking, pseudoscience specialises in policy-based evidence making. Today, this infection is spreading.
Two egregious examples show just how easy it is to subvert the scientific process. The campaign by Andrew Wakefield against the MMR vaccine, recently boosted by Robert De Niro’s support, is pseudoscience.
So is the campaign against glyphosate (“Roundup”) weedkiller, which has now resulted in the European parliament recommending a ban on its use by gardeners.
A large dossier claiming to find evidence that glyphosate is “probably carcinogenic” was published last year by the International Agency for Research on Cancer (IARC), part of the World Health Organisation. What could be more scientifically respectable?
Yet the document depends heavily on the work of an activist employed by a pressure group called the Environmental Defense Fund: Christopher Portier, whose conflict of interest the IARC twice omitted to disclose. Portier chaired the committee that proposed a study on glyphosate and then served as technical adviser to the IARC’s glyphosate report team, even though he is not a toxicologist. He has since been campaigning against glyphosate.
The IARC study is surely pseudoscience. It relies on a tiny number of cherry-picked studies, and even these don’t support its conclusion. The evidence that it causes cancer in humans is especially tenuous, based on three epidemiological studies with confounding factors and small sample sizes “linking” it to Non-Hodgkin lymphoma (NHL). The study ignored the US Agricultural Health Study, which has been tracking some 89,000 farmers and their spouses for 23 years.
The study found “no association between glyphosate exposure and all cancer incidence or most of the specific cancer subtypes we evaluated, including NHL . . .”
A bit more about glyphosate and its actual toxicity:
Dose for dose, glyphosate is half as toxic as vinegar, and one tenth as carcinogenic as caffeine. Not that coffee’s dangerous — but the chemicals in it, like those in virtually any vegetable, are dangerous in lab tests at absurdly high concentrations. So is dihydrogen monoxide, for that matter, if you inhale it, drink it to excess or let its gaseous form burn your skin (that’s H2O, by the way).
Besides, risk is hazard plus exposure, a point ignored by the IARC. If you routinely put coffee down your throat, you are exposing yourself to the infinitesimal hazard caffeine represents. If you spray a little Roundup on your garden path, you are not even exposing yourself to the more infinitesimal hazard of glyphosate.
Roundup is probably the safest herbicide ever, with no persistence in the environment. But the Green Blob hates it for three reasons. It’s off-patent and therefore cheap. It was invented by Monsanto, a company that had the temerity to make a contribution to reducing famine and lowering food prices through innovation in agriculture. And some genetically modified crops have been made resistant to it, so that they can be weeded after planting by spraying, rather than tilling the ground: this no-till farming is demonstrably better for the environment, by the way.
Tempest in a teapot - I use the stuff for prepping the garden beds on spring - wait for a couple of nice days and go through with a power sprayer. Knocks the beds down so I don't have to dig as much and I use mulch through the growing season for crop health and weed supression. The combination works great.
It is a pity that some people are so suceptible to a narrative without doing even the most minor fact checking.