The Legacy of Phylloxera in Grapevines

Phylloxera in Grapevines

The legacy of phylloxera in grapevines is vast. It decimated more than 40% of France’s vineyards by the 1870s. Today, France consumes more Scotch whisky than the entire production of cognac. Despite phylloxera’s devastating effects, France is now an acclaimed wine country and a major player in the wine industry. Its legacy is a fascinating and sometimes tragic story.

The severity of phylloxera infestation depends on the source and sink materials of the plant. While the defoliation effect affects the yield of a vine, the infestation itself can affect the yield of the whole vineyard. The Britzingen vineyard had a higher crop load than the Pfaffenweiler vineyard. However, this was not evident in yield data. The hybrid “Seyve-Villard 18-315” vine grew more than 15% more after the phylloxera-eradication program.

Researchers found that phylloxera reduces the photosynthetic capacity of healthy tissue surrounding a gall while lowering it on the adjacent leaf area. These changes are minor, but the authors suggested that the process is also possible during a phylloxera infestation. Insects attack grapes and create galls that contain high levels of starch. The larvae then feed on this starch and thus reduce the plant’s photosynthetic capacity.

The Legacy of Phylloxera in Grapevines

Pecan trees also develop galls to protect the fruit from pecan phylloxera. The pests usually attack fruit, shoots, and leaves. It is important to treat the galls early in the following year to ensure maximum protection. One of the most common symptoms of pecan phylloxera infestation is galls. It’s best to treat pecan trees at the earliest sign of infestation. The pests can cause significant damage to pecan orchards. Symptoms of pecan phylloxera infestation include brownish spots on the leaves and yellowish fungus.

Despite the fact that phylloxera had already caused a significant damage in California, many scientists were under the impression that phylloxera was just a symptom and not a cause. As time passed, more scientists came to accept that phylloxera was actually the cause of the disease. By 1869, phylloxera was found to dry out vines and destroy entire crops. It is now one of the most destructive insects that can affect a vineyard.

Despite the detrimental effects of phylloxera, the overall effect of leaf infestation at the Baden vineyard was minor. The effects on hybrid grapes were minor, but visible. Commercially cultivated V. vinifera grapevines may suffer from reduced storage of carbohydrates and altered biochemical processes. These changes, however, can result in lower crop yields and a decreased lifespan. This pest’s legacy will continue to threaten grapevines throughout their history.