Phylloxera
attacks the roots of grape vines and eventually kills the plant.
It can take up to ten years from the time a plant is infested
with phylloxera until the vine finally dies. During
that period of decline, the quality of the grapes produced by
the vine remains high though the quantity of fruit produced diminishes
each year.
The Phylloxera is a root louse and is so small it is
nearly microscopic. In the second half of the 19th century (the
late 1800s) Phylloxera appears to have been accidentally imported
from its native North America into Europe. When Phylloxera arrived
in Europe, it nearly destroyed the vineyards there. The
terrible destruction was only halted when biologist working in
Texas discovered that it was possible to use the root stock of
Vitis Labrusca (native American grapes) and graft the Vitis Vinifera
(wine
grapes) grape vines on them. Since Phylloxera does
not attack the roots of the native American grapes, the vineyards
could be replanted with the new grafted root stocks.
Phylloxera is now a problem in California,
New
Zealand and some parts of South America. Rootstocks
like AXR1 that were developed around 1970 were planted because
they solved a number of fungus and disease issues. Unfortunately,
the fact that those rootstocks are attractive to Phylloxera means
that they are being replanted.