Test weedkiller more before banning it
Banning herbicide glyphosate would affect smaller vignerons, says Jonathan Hesford
The French government is currently discussing the idea of banning glyphosate, the weedkiller first sold under the brand-name Roundup. The ban has received a large amount of support from the general public based on various stories in the media about it being linked to cancer. However, the majority of farmers are against the ban. So what are the implications for viticulture and wine production?
I don’t have space in a wine column to discuss the large number of studies, hypotheses, research papers, anecdotal stories and opinions that surround the risk glyphosate may or may not pose to human health.
However, I will say that the bulk of the scientific, peer-reviewed research concludes that glyphosate does not pose any significant risk to humans, even though a handful of papers suggest a potential link to some forms of cancer in animals.
Glyphosate does pose a known risk to aquatic life though. So spraying it where it can run off into streams, lakes or the sea before it breaks down is environmentally harmful. Also, blanket spraying will lead to dead soils lacking organic material and prone to erosion.
Glyphosate is a systemic weedkiller that attacks the photosynthetic pathway of many green plants, killing targeted weeds within a week or so. It is cheap, effective in low doses against a wide range of weeds and does not have any toxic or irritant effects on people using it.
It breaks down into harmless molecules over time in the soil and does not affect the roots of nearby plants or crops. Therefore it has been the weedkiller of choice for many forms of agriculture as well as use in parks, pavements and public spaces. It’s also readily available for the public to use at home in the garden.
Normally, glyphosate would not enter the human body as it is not sprayed on food crops. However the development of “roundup-ready” corn, which is genetically modified to make it glyphosate-resistant, means such corn is sprayed. Note that GE crops are not permitted in the EU.
In addition, glyphosate has been sprayed on wheat and barley in order to speed up the desiccation of the grains just before harvest, preventing mildew and rot but leaving a small but detectable residue on the grains used to make flour, bread, pasta and beer.
In viticulture it is used to varying extent, depending on the terroir and the philosophy of the vigneron. Some growers rely on it too much, in my opinion, spraying it on the whole of the vineyard floor, several times a year, rather than just in the spots which are difficult to plough or mow. Some vineyards, such as those on steep slopes or with very stony soils, are very difficult to weed mechanically.
Organic producers are prohibited from using glyphosate or any other chemical weedkiller and have to rely on mechanical, manual or physical methods, such as burning.
Because vines are not directly sprayed with glyphosate and it cannot be absorbed by the roots. Wine will not contain any residues even if the soils are treated. So there is no health risk.
The problem with banning its use in all forms of agriculture is that there are other available herbicides. These are generally known to be more toxic and more environmentally harmful than glyphostate. Some, notably pre-emergent ones, are persistent in the soil for several years. If vignerons are prevented from using glyphosate they will be likely to increase their use of these other products.
Glyphosate is the cheapest way to keep weeds out of the vineyard, therefore the vast majority of cheap wines rely on it to keep prices down. Banning it could raise the price of all wine to that of the cheapest organic bottle.
Also, if France unilaterally bans glyphosate, the lower end of the wine market would almost immediately be replaced by wines from other EU countries, destroying the market and livelihoods of thousands of producers and cooperative growers.
So while it may seem like a good, safe move to the layman, banning it would have a severe economic and possibly environmental impact on the French wine industry.
A more sensible move would be to scientifically investigate the true health risks and then, if necessary, put in place restrictions and practices on the purchase and use of glyphosate to limit those risks.
Jonathan Hesford has a Postgraduate Diploma in Viticulture and Oenology from Lincoln University, New Zealand and is the owner, vigneron and winemaker of Domaine Treloar in the Roussillon – visit www.domainetreloar.com.
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