© Caroline Henry

One of the team of "butterfly confusers" out among the vines

It's a damp and cold morning when the 34 vineyard workers of the “Goutte d’Or” co-operative gather for coffee at the winery's pressing center in Vertus. They are part of a 450-strong group taking part in the village's annual butterfly confusing event, which takes place each spring. It's a big event for local producers and grape growers, who round up all the staff they can muster to place diffusers around the village's 863 hectares of vineyard.

After a quick rundown of instructions, the workers are divided up in small groups, receiving wet weather gear and a bucket full of diffusers, known as raks, before they are dispersed into the vineyard. For the rest of the morning they walk up and down every third row, attaching a diffuser at three-meter intervals in the top wire. The diffusers will remain in the vineyard for the whole growing season and only be removed next winter, by the pruners, when the empty diffusers are returned to the suppliers for recycling.

An added benefit of the communal approach is that it stimulates co-operation through the pleasure engendered by being among the vines. Workers laugh and joke while walking the vineyard, and at the end of the morning everybody looks forward to a three-course lunch.

The rak is a small device, akin to a plastic coat hanger. It is filled with pheromones, the hormones dispatched by the female cochylis butterfly to attract her mates. When the pheromones are artificially released, the male butterflies are overwhelmed by the vast number of female signals. They are pulled in several directions and, not knowing where to go, they panic and flee from the area. As a result, the female butterflies will not be fertilized or lay eggs which would turn into “grape worms."

The pesky grape worm is dangerous for the vines as it feeds on leaves and buds – and later in the year on the grapes themselves – which often results in grape rot. Traditionally, winegrowers treat against grape worm by spraying insecticides several times during the growing season. But the diffusers provide a greener way to combat the disease.

The village of Vertus decide to implement preventative action four years ago, at the request of Pierre Larmandier, the local manager of the grower group, the Syndicat des Vignerons. Since then, the adoption rate has risen from 50 hectares to more than 800 hectares.

© Caroline Henry

L-R: Buckets full of "raks"; the communal lunch; the diffusers are attached at 3-meter intervals

The organization of the butterfly confusion event is probably the biggest operation in the village besides the vintage. Planning starts in January and is co-ordinated by Bryan Geoffroy, the local technical manager of the CIVC (Comité Interprofessional des Vins de Champagne).

First, the 820 growers of the region receive a survey asking if they want to participate in the event. If the answer is yes, they are asked to choose their supplier for the diffusers. Once all the responses have been gathered, the diffusers are ordered from six different suppliers and dispatched to the coordinators of each sector. In Vertus, there are six sectors: five are co-operative based, while the sixth is made up of Champagne houses and independent growers.

The Vertus area covers several villages and lieux-dits: Vertus, Bergères les Vertus, Coligny, Voipreux and Villeneuve. With 863 hectares of vines it is one of the biggest terroirs in Champagne, and the local operation to place the butterfly confusing diffusers is the largest in France.

Just over 95 percent of the growers participate and this year diffusers covered 815 hectares of vines. For practical reasons the work is spread over three days in the third week of April, although the bulk of the operation takes place on the Tuesday. A small amount is left until the last day as this allows the organizers to gather all the open bags of diffusers from the other groups to finish the operation.

The high participation rate is closely linked to the almost 100 percent success rate of this preventative action. The pheromones diffusers were first tested in Switzerland and Germany in the 1970s, and trials started in Champagne in the mid-1990s. At first, adoption was slow, but in the last five years things have changed – mainly because of continuous promotion by the CIVC. Today, the butterfly confusion technique is used across 13,000 hectares in the region. This figure makes Champagne the biggest adopter in France by a long way.

When it's time for lunch, the rain is quickly forgotten as the Champagne flows freely. The volunteers exchange stories, gossip, and catch up on what has been happening since the last vintage. The mood is jolly and the community cherishes this opportunity to come together at the beginning of the growing season. The male butterflies won't be so happy.