Great French Wine Blight

There have been several theories proposed for why the phylloxera was ignored as the possible cause of the disease that resulted in the failure of so many vineyards, most of which involve the feeding behaviour of the insect, and the way it attacks the roots.[5] The proboscis of the grape phylloxera has both a venom canal from which it injects its deadly venom and a feeding tube through which it takes in vine sap and nutrients. As the toxin from the venom corrodes the root structure of a vine, the sap pressure falls and, as a result, the Phylloxera quickly withdraws its feeding tube and searches for another source of food. Thus, anyone digging up a diseased and dying vine will not find Phylloxera clinging to the roots of the plant.[6]

For a few centuries, Europeans had experimented with American vines and plants in their soil, and many varieties were imported from America without regulation, disregarding the possibility of pest transfer, and related problems. Jules-Emile Planchon, a French biologist, who identified the Phylloxera in the 1860s, maintained that this transfer of American vines and plants into Europe greatly increased between roughly 1858 and 1862, and this is how the Phylloxera was accidentally introduced to Europe around 1860,[7][8] although the aphid did not enter France until around 1863.[9] The advent of steamships may have been a factor: the ships were faster than sailships so the Phylloxera were able to survive the quicker ocean voyage.[4]

The first known documented instance of an attack by the Phylloxera in France was in the village of Pujaut in the department of Gard of the former province of Languedoc,[10] in 1863.[9][11] The wine makers there did not notice the aphids, just as the French colonists in America had not, but they noted the mysterious blight that was damaging their vines. The only description of the disease that was given by these wine growers was that it 'reminded them distressingly of "consumption"' (tuberculosis).[4] The blight quickly spread throughout France, but it was several years before the cause of the disease was determined.[4]

Charles Valentine Riley in 1870 confirmed the theory proposed by Planchon.

Over 40% of French grape vines and vineyards were devastated over a 15-year period, from the late 1850s to the mid-1870s. The French economy was badly hit by the blight; many businesses were lost, and wages in the wine industry were cut to less than half. There was also a noticeable trend of migration to, among other places, Algiers and America. The production of cheap raisins and sugar wines caused problems for the domestic industry that threatened to persist even after the blight itself. The damage to the French economy is estimated to have been slightly over 10 billion Francs.[4]

Research into identifying the cause of the disease began in 1868, when grape growers in Roquemaure, near Pujaut, asked the agricultural society in Montpellier for help.[12] To investigate the disease, the society appointed a committee consisting of botanist Jules Émile Planchon, local grower Felix Sahut, and the society's president, Gaston Bazille, among others. Sahut soon noticed that the roots of dying vines were infested with "lice",[13] which were sucking sap from the plants. The committee named the new insect Rhizaphis vastatrix.[14] Planchon consulted French entomologists Victor Antoine Signoret and Jules Lichtenstein (Planchon's brother-in-law). Signoret suggested renaming the insect Phylloxera vastatrix, due to its similarity to Phylloxera quercus, which afflicted oak leaves.[15] In 1869, English entomologist John Obadiah Westwood suggested that an insect that had afflicted grape leaves in England circa 1863 was the same insect afflicting grape vines' roots in France.[16] Also in 1869, Lichtenstein suggested that the French insect was an American "vine louse" that had been identified in 1855 by the American entomologist Asa Fitch, which he'd named Pemphigus vitifoliae.[17] However, there was a problem with these suggestions: French grape lice were known to infest only a vine's roots, whereas American grape lice were known to infest only its leaves.[18] The British-born American entomologist Charles Valentine Riley had been following news of the outbreak in France. He sent Signoret specimens of American grape lice, which Signoret concluded – in 1870, while besieged in Paris during the Franco-Prussian War – were indeed identical to French grape lice.[19] Meanwhile, Planchon and Lichtenstein had found vines with afflicted leaves; lice that were transferred from those leaves to the roots of healthy vines attached themselves to the vines' roots as other French grape lice did.[20] Also in 1870, Riley discovered that American grape lice wintered on American grape vines' roots, which the insects damaged, albeit less than in the case of French vines. Using American grape vines and American grape lice, Riley also repeated Planchon and Lichtenstein's experiment, with similar results.[21] Thus the identity of the French and American grape lice was proved. Nevertheless, for another three years, a powerful majority in France argued that Phylloxera was not the cause of vine disease; instead, vines that were already sickly became infested with Phylloxera. Thus, in their opinion, Phylloxera was merely a consequence of the "true" disease, which remained to be found.[22] Regardless, Riley had discovered American grape varieties that were especially resistant to Phylloxera, and by 1871, French farmers began to import them and graft French vines onto the American rootstock.[23] (Leo Laliman had suggested importing American vines as early as 1869, but French farmers were reluctant to abandon their traditional varieties. Gaston Bazille then proposed grafting traditional French vines onto American rootstock.[24]) However, importation of American vines did not entirely solve the problem: some American grape varieties struggled in France's chalky soils and succumbed to Phylloxera.[25] By trial and error, American vines were found that could tolerate chalky soils.[26] Meanwhile, entomologists worked to unravel the strange life cycle of Phylloxera, a project that was completed in 1874.[25]

Many growers resorted to their own methods in attempt to resolve the issue. Chemicals and pesticides were used to no avail. In desperation, some growers positioned toads under each vine, and others allowed their poultry to roam free in the hope they would eat the insects.[27] None of these methods was successful.

After Charles Valentine Riley, Missouri's state entomologist, confirmed Planchon's theory, Leo Laliman and Gaston Bazille, two French wine growers, both suggested the possibility that if vinifera vines could be combined, by means of grafting, with the aphid-resistant American vines, then the problem might be solved. Thomas Volney Munson was consulted and provided native Texan rootstocks for grafting. Because of Munson's role, the French government in 1888 sent a delegation to Denison, Texas to confer on him the French Legion of Honor Chevalier du Mérite Agricole.[28]

The method was tested, and proved a success.[29] The process was colloquially termed "reconstitution" by French wine growers. The cure for the disease caused a great division in the wine industry: some, who became known as the "chemists", rejected the grafting solution and persisted with the use of pesticides and chemicals. Those who became grafters were known as "Americanists", or "wood merchants".[6] Following the demonstrated success of grafting in the 1870s and 1880s the immense task of "reconstituting" the majority of France's vineyards began.

The French government had offered over 320,000 Francs as a reward to whoever could discover a cure for the blight. Having reportedly been the first to suggest the possibility of using the resistant American rootstock, Leo Laliman tried to claim the money, but the French government refused to award it, with the rationale that he had not cured the blight, but rather stopped it from occurring. However, there may have been other reasons for the government denying Laliman the prize: he was mistrusted by several notable parties, and he was thought by many to have originally introduced the pest.[4]

A vineyard in present-day France.