From the beginning of contact between Europe and America, plants were shipped in both directions. Wheat to America, potatoes to Europe, there were many great successes from this transfer. In the early 1800s, botanists began experimenting with crossing native American vines with European vines, trying to produce better grapes. The introduction of fast steamships permitted American vine samples to survive the passage across the Atlantic.
The thought that this could lead to eco-disasters did not cross anyone’s mind. Nobody was particularly concerned when French vineyards noticed that a few vines were dying. In 1863, the scale of the disaster became apparent. This new disease was now attacking French vineyards on an ever-increasing scale. Over 40% of French vineyards were destroyed within ten years: small pockets remained free of the disease, but for no discernable reason.
The disease marched ever onwards, eventually reaching around the globe as far as Australia and Argentina. Investigations were conducted, theories propounded and cures proposed, all to no avail. The French government offered a reward worth $5 million in today’s money for a cure for the disease.
Viticulturists and botanists at Montpelier in eastern France discovered a sap-sucking louse called phylloxera infesting the roots of the dying vines. As well as the damage done by boring into the root to feed, the louse opens the way for bacterial infection that finally kills the vine. Nasty! Entomologists working in France (Planchon and Lichtenstein) and America (Riley) concluded that the louse causing all this trouble in Europe was an American immigrant. Phylloxera had hitched a lift on the vine samples sent to Europe for breeding trials. The wheel turned a full circle when the phylloxera louse arrived on the West coast of USA, previously an uninfected region.
Knowing the cause did not provide a solution. Chemicals and pesticides were tried without success. More desperate measures including placing toads under each vine or allowing poultry to roam free in the hope they would eat the insects. Even more extreme was flooding the vineyards every winter to drown the pest. None of these methods worked.
What did work was grafting European vines onto American vine roots (though much work had to be done to select American rootstocks that would flourish in European soils). Today, almost all wine producing grapes around the world grow on rootstock with American parentage.
The only major wine producing country in the world remaining free of phylloxera is Chile. How long will that last, I wonder. Other unexpected consequences of the phylloxera plague are worth a further post, coming soon.
What about that reward from the French government? It was never paid. The viticulturist who had pioneered growing European vines on American rootstock claimed the prize. The French government refused to pay, claiming that he had not cured the blight, but rather stopped it from occurring.