Legacy of Phylloxera
When Professor Jo Westwood, an entomologist, and biologist at Oxford University, was given a vine leaf from a greenhouse in Hammersmith in June 1863, he noticed that it was being suffocated by a small insect and its eggs. Westwood instantly recognized this parasite as Phylloxera Vastatrix, an aphid.
Initially unaware of its significance, he became the first researcher in Europe to investigate the presence of this small parasite that would forever change the wine world. Several vineyards in the Rhône Valley were being destroyed around the same time by an unknown disease.
Throughout the 19th century, a large number of plants, including vines, were transported and exchanged between America and Europe. A large greenhouse filled with tropical plants from all over the world was a must-have for rich and powerful households.
Little consideration was given to what diseases these plants might carry and schlep into the country. This oversight would be disastrous for European vine growers.
The first fungal wave, Oidium, reeked its head in Europe in 1847, assaulting vines and severely affecting the economies of wine-producing regions, followed by downy mildew in 1878 and then black rot in 1888. However, it was Phylloxera that proved to be the most lethal of them all.
The species is less than a millimeter long and hardly visible to the naked eye. It feeds on the sprout of the roots of vines, the only plant affected. It spreads to other vines by soil cracks and roots, but it can also be carried long distances by wind, agricultural machinery, or human feet. Plants that are impacted often become barren and die.
The spread of Phylloxera
The disorder spread rapidly throughout France, first to the Languedoc and then to the rest of the country. Most of Europe and North Africa were affected by the turn of the century. It has been reported that nearly half of France’s vineyards were affected. Many wine regions declined, never to recover.
Those that survived lost precious plant material and soon made the switch to higher-yielding, lower-quality grape varieties. It’s difficult to imagine how catastrophic this plague was for rural farmers who relied solely on wine for their survival.
Many people initially refused to believe that this small parasite could be to blame, choosing to believe it to be a side effect instead of the cause. It took a French government investigation in 1869 to convince people that Phylloxera was, in fact, to blame. The search for a cure took longer than it should have, owing in part to the professional rivalry between French and American researchers.
Possible treatments included flooding vineyards with water (which is effective and is still used in Argentina, though it is rarely practical), and spray coating with carbon disulfide (which is highly flammable and dangerous). Finally, in the 1880s, researchers discovered that grafting resistant American root systems onto European scions (Marcottage and Provingage) constituted the only surefire way to prevent infection. Almost every vine in a winery today is treated in this manner prior to sowing.
How did Phylloxera impact France?
Phylloxera impacted France profoundly in several ways. The scale of its wine industry was surely one of the most dramatic. Viticulture had grown steadily since the French Revolution; according to Rod Phillips, the area used to grow vines peaked in 1874 at 2,465,000 hectares, roughly three times the size of France’s total plantings today. Following phylloxera, many wine regions shrank significantly or disappeared entirely, with only a few exceptions (notably the Languedoc) growing in proportion.
Viticulture was completely redesigned. Prior to phylloxera, most vineyards in France were field blends rather than organized columns of varieties and were generally propagated en foule (“in a crowd”) through layering. A cordon, or even an entire vine (as with Provinage), was laid to rest until it established roots in this method.
The end result was a jumbled mixture of vines at densities 2 or 3 times greater than is typical today, with complex root systems that might be hundreds of years old. Cépages also made changes. Phylloxera created an opportunity to isolate the wheat from the chaff in most regions, and a plethora of widely-disliked vines was either reduced or obliterated entirely.
Grafting onto crossings of root stalks is now commonly used to combat phylloxera and other conditions that affect vine growth. Some rootstalk, for example, have been found to be resistant to phylloxera, but when grown in limestone-rich soils like those found in Burgundy, they falter because the pH interferes with their ability to absorb iron, resulting in chlorosis. The solution was to cross phylloxera-resistant root stalks with limestone-tolerant root stalks.
In natural environments, marcottage (layering) has evolved as a common method of vegetative propagation for many species. Stabbing the regions of interest to reveal the internal stem and alternatively applying rooting compounds is typical of the horticultural layering process.
The rooting process can take anywhere from a few weeks to a year. When managing a cascading or spreading plant, Marcottage can be helpful. Plants naturally continue to perpetuate in this manner, resulting in more plants without the need to sow new seeds.
Provingage (or marcotting) involves wounding the target area with an upward of 4 cm long cut kept open with a piece of wood or similar, or removing a strip of bark. The wound is then enveloped by a moisture-retaining medium, such as peat moss or cloth, and then by a moisture barrier, such as plastic film tied around it.
To encourage root growth, the rooting hormone is frequently applied to the wound. When enough roots have managed to grow from the wound, the stem is removed from the parent plant and planted. Depending on the plant species and the vigor of the parent plant, it may take a few weeks to one or more growing seasons to produce sufficient roots.
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