What is Phylloxera anyway?


Image courtesy of Bosman Family Vineyards

In the late nineteenth century, as much as two thirds of European vineyards were destroyed by a tiny insect called Phylloxera. Similar to an aphid that feeds on the roots and leaves of vines, it is one of the most feared and destructive vineyard pests – and there is no known cure.

Phylloxera has been found in virtually every wine producing country in the world. It spreads quickly and is incredibly difficult to control, especially in humid regions. Damaged roots will eventually cut off the flow of nutrients to the vine, killing it.

European vines, vitis vinifera, are particularly affected by Phylloxera as, unlike American vines, they have no natural defences. Vines native to America – like vitis rupestris and vitis riparia – are able to secrete a sticky sap that clogs the mouths of Phylloxera, meaning it can’t feed. There are very few means to control Phylloxera in vineyards planted with European varieties. One solution is to graft vitis vinefera vines on American rootstocks. Another is to plant hybrid varieties.

By the end of the nineteenth century, hundreds of hybrid varieties had been created, but many of these aren’t capable of producing good quality wine. Rootstock grafting is currently the preferred method of preventing Phylloxera outbreaks around the world.

There are, however, some varieties in certain European locations that have remained unaffected by Phylloxera: Assyritiko grown on the Greek island of Santorini, small parcels of Pinot Noir used for Bollinger and vines in the region of Jumilla are all still ungrafted. This is due to the location and soil content, with Phylloxera unable to survive in sandy soil. The isolated vineyard growing regions of Chile also has no phylloxera, although other vineyard pests such as nematodes can be just as destructive.

Phylloxera is still a threat to winemakers across the world. While it is not likely to ever fully disappear, improvements in vineyard management mean it’s improbable to pose as serious a problem as in the 1800s.

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28th September 2015

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