As Europe considers extending its authorisation, how should we be viewing its use in vineyards for wine?
What is glyphosate?
It's currently the most widely sold herbicide in the world for all types of crops, including vines. Invented by American behemoth Monsanto – in the process of merging with Germany’s Bayer – the molecule is sold by the firm under the trademark Roundup. Since 2000, however, the patent has been in the public domain and other companies market it. This is a non-selective herbicide, in other words it kills all plants when it touches their leaves. Monsanto sells seeds for genetically modified plants with a resistance to Roundup – known as Roundup Ready – but not for vines.
Glyphosate and vines
Like all plants, vines have to compete with weeds to gain access to water and soil nutrients. Were it not for human intervention, yields would be a lot lower. Traditionally, tillage was used between the rows of vines to remove weeds. Since Roundup appeared in 1974, a single spray using a tractor at the end of winter produced what was referred to at the time as the ‘magical effect’. The young shoots are immediately killed before vine leaves even start growing. Consequently, the soils stay pristine as glyphosate remains active for up to six months. However there is one known, major disadvantage – the vines don’t live as long. Another issue is that some plants develop resistance to glyphosate.
Glyphosate and wines
Like any active substance used in farming, glyphosate is subjected to a Maximum Residue Limit (MRL), that can be measured in grape juice after pressing. Similarly, it has to comply with a Pre-harvest Interval (PHI) and cannot be sprayed less than 28 days before harvest.
But like other agro-chemicals (fungicides, pesticides…), there is no MRL for glyphosate for wine in Europe. Although fermentation, which transforms juice into wine, and use of inputs during the winemaking process tend to reduce the amount of agro-chemicals in the finished product, lack of MRL and therefore measurement, provides scope for speculation. There is very little research on the presence of agro-chemicals in wine. French magazines RVF (December 2009) and Que Choisir (October 2013) along with Moms across America (winter 2015/2016) have all noted the presence of agro-chemicals, including glyphosate, in French and Californian wines. The amounts are minute but nevertheless show up because detection thresholds are constantly getting lower.
Glyphosate and health
The bombshell came when on March 20, 2015 WHO, via its International Agency for Cancer Research, listed glyphosate as a “probable carcinogen for man”. But the authorities are responsible for its sale and on March 15, 2017, the European Chemicals Agency (ECHA) considered it to be non-carcinogenic. So who should we believe? Should glyphosate be accused of causing an increase in the incidence of blood cancers amongst farmers? Or of gluten intolerance? The current trend is for chemical usage to increase for all types of farming. France’s decision in 2008 during the Grenelle Environment Forum to halve the amount of agro-chemicals in a decade will not be achieved. In fact, their usage has risen!
How about organic?
Although the few existing studies show that often organic (AB logo) and biodynamic wines (certified Demeter or Biodyvin) contain a little glyphosate, the doses are minute. The chemical is banned for this type of farming so any presence of glyphosate can be ascribed to contamination from neighbouring vineyards and drift during spraying.
Sustainable winegrowing, sometimes labelled High Environmental Value (HVE logo), does not outlaw glyphosate. As its use is based on wine growers’ good faith, we can only hope that they utilise it sparingly.
Can vines be grown without glyphosate?
Conventional wine growers claim this is “not realistic” or that it would imply reverting to tractor tillage which produces greenhouse gases. This is the stance taken by the PR representatives at France’s national farmers’ union FNSEA. But then again, they also recommended agribusiness as a way of combating hunger worldwide...
There are, though, techniques using ground cover which can be perennial or planted annually and involves a variety of plants including rye, clover and legumes. It can be adapted to suit different sites and has a number of advantages. Primarily, it prevents soil depletion. Whilst herbicides ultimately kill off micro fauna in the soils, intensive tillage does the same. Woodlice, nematodes, earthworms and mites all help air soils, promoting water penetration, rooting and access to nutrients. Living soils also provide vines with natural nitrogen fertilisers, and biodiversity offers protection against pathogens such as pests and diseases. None of these techniques require conversion to organic – using NO agrochemicals for at least three years is extremely restrictive. They are complicated to implement and require more labour. They are also one more illustration of how captivating wine growing can be.
Written by Alain Echalier