How can we control pests in the vineyard while being kind to the environment and without impacting the vines? ‘Confusion sexuelle’ is one way to stop one very persistent pest in its tracks. If you have visited vineyards in France, you might have heard of it but not know the ins and outs. So here are the answers to questions you might never have thought to ask.
1. Why is it needed?
The grape moth (specifically Eudemis and Cochylis) lays eggs in Spring and takes up residence. Then in summer, a future generation attacks the grapes, breaking the skin and laying the grapes open to rot eg Botrytis Cinerea (Grey rot). They aren't choosy - they will attack any grape variety.
2. So what is Confusion Sexuelle?
Translated (rather boringly) as Mating Disruption, Confusion Sexuelle is what we cause in the vines to stop the first generation of moths reproducing. A small diffuser emits pheromones of the female, the male gets so confused with all the pheromones in the atmosphere and cannot find the ‘nonexistent’ female, so mating doesn’t happen, eggs are not laid and so there are no caterpillars or moths to keep the reproduction going. (See short vid below)
3. What does the diffuser look like and how many do you need?
It’s a tiny slip of plastic that is attached to the lowest wire that the vine will be trained along. They are put out early April before the first arrivals. We put them every few metres across and down rows ensuring the edges of the plot are well protected - about 500-600 per hectare. It is most effective if is done over a 5+hectare area. Because Château George 7 is a small plot, then it is important that my neighbour does it too. In fact, it is a feature of some geographies, that winegrowers work together to cover a larger area.
4. Is it safe?
Absolutely. It belongs to a family called BioControl products which chemically reproduce something that is found in nature. It just diffuses into the air so doesn’t go on the plant, the soil or the grapes. It is used in organic farming as well as in other sustainable viticulture approaches and it is a great example of advances in technology helping nature to protect itself. Also, it doesn't affect other insects that we want to encourage to hang out in the vineyard.
5. Is it more expensive than insecticide?
The short answer is yes. Here at Château George 7 it is a no-brainer because we are a small property so the actual cost difference is not huge. But it can cost up to 3 or 4 times more than spraying using chemicals (the cost of the diffuser added to the time to walk up and down the vines against tractor time and chemical costs). However, it is part of a broader approach to help the vineyard be balanced and sustainable so how do you calculate the cost of not doing it? The moths’ natural predators are bats and birds so attracting more of these through biodiversity means the confusion might not be needed at some point.
6. Is this done everywhere?
No. It is used a lot in Champagne (about 40% of the vineyard area) and also here in Bordeaux across a certain percentage of vineyards and I have read about it in Franciacorta in N Italy, and in Switzerland as well as parts of Germany and Spain, but it is not an automatic vineyard practice. It tends to be done/needed more in certain climatic conditions (eg here in Bordeaux) but cost is a key driver and prohibiting factor for some.
7. Is this a new thing?
It was developed by INRA (Institut de Recherche Agronomique) in Bordeaux back in 1974 and approved by the French ministry of agriculture in 1995. In Switzerland, growers started a programme 20 years ago and there, 70% of vineyards are under ‘confusion’ today.
So voilà, one way that we tackle an unwelcome pest in the sustainable vineyard - more about trying to encourage their natural predators in a future post. In the meantime, if you have any comments, don't hesitate to share them.