The Root of the Problem: How One Pest Upended the Global Wine Industry

by Isis Quan

For many people, clearing customs is the bane of their international travel trip. These checks can cause huge delays in our plans, and sometimes we are even guilty of trying to slip contraband in our bags. We’ve heard about the threats invasive species pose around the world, but will smuggling in one little apple really make a difference? Potentially, yes. Part of the reason that customs departments exist is because of the small, seemingly innocent mistakes we’ve made when importing goods in the past. We made one such tiny mistake during the Victorian era that unleashed massive consequences we are still reeling from to this day.

Botany was all the rage during the Victorian era. Men and women traveled the world scouring the four corners for new and unique flora to bring back to their home countries. The French, in particular, were interested in discovering new grapevines to enhance their first-rate wine industry. Unfortunately, returning from trips to America during the 1860s, French botanists brought home more than they bargained for. Although American vines had been brought to France before, it is speculated that innovations in travel that made the journey quicker also allowed for an aphid-like insect known as phylloxera to survive the trip when it hadn’t before. Europe’s wine industry soon faced devastation of the likes it had never seen.

A cartoon from Punch, a British satire magazine, September 6, 1890: “The phylloxera, a true gourmet, finds out the best vineyards and attaches itself to the best wines.”

Vines across France began to wilt and die, with some areas suffering losses of up to 60% of their stock. As the French struggled to discern the cause of their new blight, phylloxera feasted on the roots of their vines. It wasn’t until 1870 that the aphid-like pest was even fingered as the villain, and it would take eight more years for a solution to be put into practice. By then, phylloxera had spread across all of Europe. As grapevines died left and right, botanists finally discovered that the solution to their problem lay in phylloxera’s American roots. A simple graft of European grape varieties onto American variety roots would stop phylloxera from killing a vine; although it would not eliminate infestation. So, with American root stock, the European wine industry was saved. Unfortunately, American roots did nothing to stop the spread of phylloxera, and eventually the pest reached every continent where grapevines grew, forcing almost every vigneron and farmer to adopt the grafting practice. All attempts at killing off the phylloxera, the root of the problem, had failed.

The Homestead’s Demonstration Vineyard features varieties of grapes cultivated from grafted root stock.

So how and why were phylloxera so devastating? Interestingly, the aphid-like insect feeds largely on the leaves of American vines, but on European vines it feeds on the plant’s roots. This leads to the death of the vines as the aphid causes open wounds in the vine’s roots, which eventually cause fungal infection and death. The aphid itself does not directly kill the vine, the infection does. Studies on the insect have revealed that they do indeed also feed on the roots of American varieties, but that the roots are resistant enough to prevent significant damage and lead to phylloxera migrating more often to the plant’s leaves. Additionally, the insect can produce both asexually and sexually, as well as develop both winged and non-winged forms. Its ability to adapt has allowed it to procreate rapidly, as well as spread quickly. It has also proven quite difficult to fully study the insect, which may be why a permanent solution to the pest has yet to be found.


A leaf blighted by phylloxera courtesy of Beatriz Moisset.

While smuggling a single apple through customs might not seem like a big deal (apples are found around the world, after all), the potential bacteria or insect infestation from the apple might cause a huge problem. French botanists had no idea that importing a few grapevines would change the roots of their industry forever, or that to this day we would still be battling the pest in almost every vineyard. Their tiny mistake led to the loss of vines that had weathered hundreds of years, and wiped out an unknown number of non-cultivated “wild” vine species. The French did not have the knowledge of invasive species that we do today, but we can learn from their mistakes and make more conscientious decisions about imports today.

Healthy leaves in the Homestead’s vineyard.

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