A tunnel shelters vines from 80% of plant protection products

tunnel formed by two stainless steel tubes which unroll a waterproof tarpaulin over vines when a sensor at the end of the row detects that the predefined humidity threshold has been exceeded, could provide a way of reducing plant protection products. The cover retracts in two minutes when the rain stops. “I thought that this could be a solution for avoiding the onset of downy mildew, black rot and dead arm disease without resorting to spraying”, explains Patrick Delmarre who has been leading the Viti-Tunnel project since 2017.

“The system also works in the event of hail. Conversely, the engine does not start when the sensor detects dew”, explains the new start-upper. He convinced ten prominent chateaux on the right and left banks of Bordeaux to pay €17,000 to test the Viti-Tunnel over three 50-metre rows for two years.

Their motivations for joining the project differ. Blandine de Rouffignac, R&D manager at Château Margaux, sees it mainly as an excellent way of eliminating copper and protecting rivers and streams, whereas staff at Château Haut-Brion are considering using the technique near residential areas, schools and the retirement home that border their vineyards.

In spring 2019, Patrick Delmarre successfully covered 1.5 km of vines with his system. “I wanted to install it in as many vineyards as possible to be sure of encountering downy mildew”. There were relatively few occurrences of the blight as it happened but the 2019 vintage helped Delmarre tweak his prototype. Strong disease pressure in 2020 was a godsend for Delmarre. The Viti-Tunnel was triggered between 508 and 669 times depending on the site, covering the vines for up to 11.6 days.

“Its efficiency exceeded my expectations! It contained the spread of downy mildew very well on both leaves and clusters, whereas the disease caused a drop of up to one third of the crop in classically treated vines”, claimed Delmarre.

Nicolas Aveline of the French Institute of Vine and Wine (IFV) confirmed the findings. From April to September, the engineer visited all the plots once a week to compare the spread of diseases in the rows covered by the Viti-Tunnel and in neighbouring rows. “Each time, I took measurements on 100 leaves and 100 bunches of grapes”, he explained. “Both in frequency and intensity, the Viti-Tunnel invariably did at least as well as the fungicides. At Château Mouton Rothschild, it protected 99% of the clusters, whereas the frequency of onset was 48% in neighbouring rows”.