The quest to abandon pesticides

As climate change brings more virulent pests, grape growers need alternative pesticides. Sophie Kevany reports on the current options.

Philippe Bardet, president of Bordeaux´s SME association
Philippe Bardet, president of Bordeaux´s SME association

Reading through lists of common European vineyard pests and diseases, to say nothing of the pictures, can make the fact that wine exists at all seem miraculous: mildew, flavescence dorée, bois noir, maladie du bois (trunk diseases) and the many forms of rot are just a few of the most common things that can strike a vine. Equally hair-raising are the chemicals traditionally used to treat them. A study of the French website of multinational chemical company BASF offers a selection. 

Futura for black rot, active ingredient dithianon is one. It carries a CMR (carcinogenic, mutagenic and toxic for reproduction) pictogram warning of a person with what looks like an exploding star in their chest. Under European Union rules, a CMR warning means the substance is “of specific concern due to the long term and serious effects that they may exert on human health”. 

Another, an anti-mildew treatment, is Enervin, active ingredient ametoctradin. And to combat the insects that cause flavescence dorée there is Mageos MD, active ingredient alphamethrin. Both carry CMR warnings. 

Asked for clarification the European Chemicals Agency (ECHA) said Futura is classified as a CMR, while Enervin and Mageos MD are classified as STOT RE (H373) – or Specific Target Organ 
Toxicity with repeat exposure.

Alternatives that work

Happily, there are also less toxic BASF offerings, notably Rak, which contains pheromones that cause sexual confusion in pests. These chemicals are used to control the cater-pillars known as cochylis or grape worm, which munch on grapes, opening them up to various kinds rot. Pheromones are part of a newer set of treatments often called biocontrol products. These include bacteria, essential oils and seaweed-based sprays. While pheromones have been welcomed by growers, anti-pesticide lobbies and traditional pesticide sellers, not all biocontrol products are as successful. For BASF, pheromones are responsible for the “strong increase” in its French wine sector insecticide sales over the past few years, while demand for fungicides “remains stable”. 

Pheromones work best when used collectively, and success stories come from areas including northern Italy’s wine producing Franciacorta region. Here, the local cooperative distributed them free to growers, said Henriette Christensen, senior policy advisor for the pesticide control lobby group Pesticide Action Network (PAN) Europe. But  pheromones sales aren’t the whole story. While EU directives (notably 2009/128/EC, aimed at encouraging ‘sustainable’ use) point to a clear agreement on the need to reduce the use of toxic chemicals in agriculture, it’s not happening. Instead, by some measurements, pesticide sales are not only stable, but increasing. 

Measuring toxicity

How pesticide usage is measured is contentious – the options are weight versus active dosage. Currently, EU pesticide data usage is based on weight sold, despite the fact that commercial pesticides are lighter than both copper and sulphur, the elements used in organic viticulture. In France, an EU agricultural heavyweight and one of Europe’s hungriest pesticide consumers, the most recent measures are based on the number of active substances per dosage unit, or Nodu (nombre de doses unités). The latest data indicates an increase of 12% in total agricultural pesticide use between 2014 and 2016. This figure is all the more embarrassing given that it happened in the middle of Ecophyto, the French government’s 2008 to 2018 flagship pesticide reduction plan, which aimed to cut pesticide use by half. As flaws in the plan emerged, it was followed by the launch of Ecophyto II and, most recently, a consultation period for Ecophyto II+, which closed in December 2018. The revised Ecophyto goals are a 25% reduction by 2020 and a 50% reduction by 2025, aided by a further €71m ($81.17m), in addition to the original €40m.  

Beyond headlines about pesticide usage and measurement controversies are the infinitely sadder ones about the environmental effects of these products. In March 2018, France’s Le Monde newspaper reported that a study by the French governmental research body CNRS and the French National Museum of Natural History showed birds were disappearing at “vertiginous speed” and linked the disappearances to modern agricultural practices that include snatching up wild land for cultivation and the use of neurotoxic insecticides known as neonicotinoids. In June 2018, the same newspaper said the National Forests Office was seeing a rapid fall in bird and bat numbers, again mainly due to pesticide usage, and the growing area of natural lands being turned over to farming. Similar examples can be found across Europe over the past five to ten years, along with numerous reports of catastrophic falls in insect numbers. For proof, see the clean windshields of cars on long journeys, which were once covered in insect bodies. 

Beyond the intense gloom engendered by those headlines, along with the EU data and France’s Ecophyto failure, there is cause for hope at a more local level. In December 2018, for example, the Bordeaux Wine Council celebrated ten years of improving the area’s environmental profile. The region’s growers have been at the forefront of the French wine sector’s clean-up efforts, both in terms of reducing CO2 production and toxic vineyard chemicals. 

Successes during this period include a 30-fold increase in environmentally engaged vineyards, which rose from 28 to 800 between 2010 and 2018. These vineyards are known as SMEs (Système de Management Environnemental), a classification based on the International Organisation for Standardisation authority framework, ISO 14001. At a broad level, their report said 60% of Bordeaux’s winemakers were involved in some kind of environmental initiative in 2017, up from 55% in 2016. 

All of that is good news for human, soil, insect, plant and planetary health. As are the ever growing numbers of producers switching to the many and varied systems of pesticide reduction, which include organic, biodynamic, vegan, integrated pest management (IPM), agriculture raisonnée (sustainable agriculture) or, more recently, agroecology. The last is defined by Merriam Webster as being “an ecological approach … that views agricultural areas as ecosystems and is concerned with the ecological impact of agricultural practices”. What’s less good news is that changing weather patterns are making that switch harder. 

What doesn’t work

Philippe Bardet, the president of Bordeaux’s SME association and an agroecological wine producer in Bordeaux’s Saint-Émilion region, offers an example. Despite his years of experience, engagement and broad knowledge of subsidies and support programmes, he says his greatest difficulty remains finding non-toxic ways to control mildew. 

“This year [2018], in Saint-Émilion South, we had 53 mildew contamination days,” he said. These are the days when mildew infections are possible, rather than actual infection levels. “That’s the highest level since the beginning of the mathematical model prediction surveys 20 years ago,” he said. At the same time, the 2018 mildew period was more virulent, longer and earlier, meaning it clashed with the flowering period when the vines are more vulnerable. The other problem is more rain, which makes it difficult to spray and washes off what’s there. For Bardet that meant 15 days when the vines were not protected because of the weather.

Asked how he’s coping, he said it’s about adaptation. For example, he bought more sprayers, meaning the nozzles he uses to deliver preventative sprays. “For the first time, we had one sprayer for every 10ha.” And in those sprayers? “We stopped using CMR products ten years ago. Instead, we use copper, as little as possible, and other ‘soft’ products such as homeopathic treatments and biocontrol methods.”

Other adaptations have been more philosophical. “Since we stopped using CMR, I have learned to live with mildew,” he says, mainly by using yield targets – the number of hectolitres of wine he wants from each plot – rather than a zero mildew target. In most of the vineyard, Bardet said he achieved 80-100% of his yield targets last year. What did not go so well were the plots where he was experimenting with newer CMR alternatives and trying to reduce the need for controversial copper, viewed as a less harmful mildew solution. 

“We had 10ha where we used copper in microdoses, along with a special herbal infusion,” he says. While total annual copper usage on all 10ha was 6.7kg, the results were not great: he reached only 60-80% of his yield target, plus he had to apply the treatments much more often than usual. 

On another 12ha, Bardet went further and used only biocontrol products, which he described as pioneering, expensive and, this year, unsuccessful. At the start of the experiment his goal was zero copper. However, as soon as the mildew symptoms appeared, he brought it back into play. But it was too late. “It was my mistake and it really dramatically impacted yields.” Only 50hl of wine were harvested from those 12ha – about 4hl per hectare. His yield objective had been ten times that, at 42hl per hectare. It was, he said, “a disaster”. 

Vineyard team morale also took a hit. “When I used CMR products, the team only had to apply them a few times, much less than biocontrol, copper or other milder treatments. And they are effective. And cheaper.” Under the new, less toxic treatment plan, he said, “everyone blames someone for the problems … it’s difficult [for them] to see so much mildew damage. Now they have no morale and I have no money.” But defeated he is not. Next year he will try again with a new seaweed-based treatment, although on fewer experimental hectares. 

By contrast he said, his insect situation is much improved – meaning there are more. “We have found the right balance. We have encouraged enough carnivorous insects to eat herbivorous insects.” The solution was a combination of understanding what chemicals killed the carnivores, then avoiding their use, as well as letting the grass between the vines grow. “That attracts the herbivores, which then attracts the carnivores to eat them. Every pest has a predator. Plus we don’t use weed killer anymore. It’s a very virtuous cycle.”

Whether that bodes well for insects, birds, bats and other species more broadly is yet to be seen. The likelihood is that more dramatic measures may be required. One suggestion, from the Pesticide Action Network and MEP Éric Andrieu, chair of the Special Committee on the EU’s authorisation procedure for pesticides (PEST), is to plant disease resistant vines. In October last year Andrieu organised a resistant variety tasting. 

Would Bardet try those? Not yet, he says. And he is not the only one. Grubbing up and replanting is costly, time consuming and Bardet is not yet fully convinced there will be no loss of taste quality. But he will continue to go to tastings and follow developments, he said. And if it turns out that the future is a choice between that and having to move his vineyards northward to escape poor growing conditions, the grubbing up might not seem so onerous.

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