The Great Crises

Three Plagues: Oïdium, Phylloxera and Mildew (1851–1900), in Data

How three imported vine diseases reshaped Bordeaux between 1851 and 1900: oïdium, phylloxera and mildew: and the treatments that answered each.

Three vine diseases reached the Bordeaux vineyard between the early 1850s and the 1880s, and none of them was native to Europe. Oïdium came first, phylloxera second, downy mildew third. Each forced growers to invent or import a new defence, and two of those defences, sulfur dusting and copper spraying, are still on the vineyard calendar. The episode is usually told through anecdotes: the American aphid, the flooded vineyards, the leaves stained blue by copper. It is rarely charted. Set against the long series of French wine production compiled by Anderson and Pinilla at the University of Adelaide, the three outbreaks read as one measurable break, the point at which European viticulture had to be replanted on different roots.

Oïdium (early 1850s)

Oïdium, or powdery mildew, is a fungus of North American origin. It spread through French vineyards in the early 1850s and coated leaves and berries in a grey bloom. Infected fruit split. A bad attack could take most of a harvest.

It was also the first of the three to be brought under control. Growers found that dusting the vines with sulfur, applied as a fine powder known as flowers of sulfur, checked the fungus, and the treatment was established within a few years of the outbreak. Oïdium never went away. It became a managed problem instead of a catastrophe, on one condition: the sulfur had to go on every season, on every vine.

That condition set the pattern for what followed. All three diseases crossed the Atlantic and attacked a European vine that had no evolved defence against them. None was contained by a single discovery. Each ended as a treatment written into the annual calendar and repeated indefinitely. Oïdium looks like the mildest of the three only in retrospect; at the time it caused real alarm, and the speed of the sulfur remedy left growers expecting the next disease to give way just as quickly.

Phylloxera, 1870–1900

The second disease had no quick answer. Phylloxera vastatrix, a tiny sap-sucking aphid from the eastern United States, feeds on the roots of the European vine, Vitis vinifera, and kills it. The insect was identified in southern France at the end of the 1860s and moved through the Gironde during the 1870s, vine by vine and commune by commune. Because it lived underground, the damage was often far advanced before anyone understood it. A vine weakened and died with nothing above the soil to explain why.

Gilbert Garrier, in his 1989 history of the crisis, called it une guerre de trente ans, a thirty years' war running from about 1870 to 1900. His title fits both the length of the fight and the way it was fought, one front at a time, with whatever came to hand. Growers tried almost everything in turn. Vineyards on low enough ground could be flooded in winter to drown the insect, but few sites allowed it. Carbon disulfide, an insecticide injected into the soil, slowed the aphid where growers could pay for the chemical and the labour to apply it. It never eradicated it. Neither method was a cure.

The answer was botanical. Growers grafted the productive European vine onto the roots of American Vitis species, which had evolved alongside phylloxera and tolerated it. Replanting on resistant American rootstock, called reconstitution in France, became the definitive solution, and it is still the standard in Bordeaux and across the wine world today. It also meant tearing out and replanting the whole vineyard, vine by vine, at great cost and over many years. That is why Garrier's war lasted a generation.

The fight also ran through institutions. Prizes were offered for a cure, and learned commissions sat on the problem. Two camps argued it out through the 1870s and 1880s: the sulfuristes, who put their trust in chemical treatment, and the américanistes, who put theirs in grafting. American rootstock won. Garrier treats the whole episode as a social and economic upheaval as much as a botanical one. Reconstitution redistributed labour, capital and knowledge across the vineyard. Growers who could raise the money to replant came through; those who could not were ruined.

Downy mildew (1880s)

The vineyard was still replanting when the third disease arrived. Downy mildew (Plasmopara viticola), another North American organism, appeared in France in the 1880s. It came in on the American vines that were being imported to fight phylloxera. Unlike powdery mildew, it thrives in damp weather, which is the ordinary Atlantic climate of the Gironde, and it could strip the foliage from a healthy young vine.

The remedy came out of the Bordeaux vineyard itself, and it is one of the best-known episodes in the history of plant protection. Growers near the city had been painting the roadside rows of their vines with a blue-green mixture of copper sulfate and lime, to discourage passers-by from taking the grapes. Those treated vines turned out to resist mildew. Formalised in the 1880s, the mixture became bouillie bordelaise, or Bordeaux mixture. It was the first widely used fungicide, named after the region where it was developed, and refined versions of it are still used worldwide. Phylloxera had required a botanical answer; mildew got a chemical one. An annual copper spray joined sulfur dusting as a fixed part of the growing year.

Prices and markets, 1870–1911

The market did not move in a straight line. The clearest account of the economic aftermath is James Simpson's 2004 working paper on France's domestic wine markets between 1870 and 1911, which describes a sequence rather than a single slump. Phylloxera first caused scarcity. Production fell, wine became dear and prices rose. Those prices drew in wine from elsewhere, both imports and the output of newly planted regions, and encouraged adulteration: wine stretched or faked outright to meet demand while prices were high. Then the replanted vineyards came back into bearing while the imports kept arriving, and scarcity turned into its opposite. Simpson's third phase is overproduction, with falling prices and a glut. Within a single generation, a crisis that began as a shortage had become a surplus.

What did not change back

By 1900 the vineyard was not the one that had entered the crisis in the 1850s. Every quality vine now grew on grafted American rootstock, a structural change that has never been reversed. Because replanting had to happen all at once and cost so much, growers settled on fewer, proven grape varieties, and the ampelographic diversity of the region narrowed. The adulteration Simpson describes, stretched, imported and mislabelled wine sold into a hungry market, built up the pressure that over the following decades pushed France toward a legal definition of origin and then the appellation system. That later story starts here, with Garrier's thirty years' war and the two fungal diseases on either side of it.