Phylloxera Infection [fihl-LOX-er-uh]
Phylloxera is a small parasitic insect belonging to the hemipterous
family. It sucks the nutrients from the roots of vines. The vine is
starved, and the fruit yield is dramatically decreased. Vines can
be infested for up to two years or even longer before any Phylloxera
symptoms become apparent in the vines.
Phylloxera symptoms include:
- Leaves turn yellow
- General deterioration in vine health
- Reduction in fruit yield
Phylloxera is native to the eastern United States; however American
rootstocks are resistant. Phylloxera was transmitted to Europe from
America in the 1860s causing widespread devastation to French and
other European wine areas. Grafting the vines onto imported American
rootstocks saved the European wine industry. The parasite eventually
spread to other parts of the world including New Zealand, Australia
and South Africa.
Phylloxera was first identified in the Central Otago wine region
in 2002. In 2006 a new infestation was discovered at Lowburn in Central Otago.
Many of the vines in the Central Otago region are still
own rooted ungrafted vines and are susceptible to Phylloxera
infestation. Phylloxera infection is transmitted by contaminated
wind borne soils and on farm machinery, and once present in a wine
region its wide dissemination is inevitable. Once infected with
Phylloxera, grapevines suffer a progressive decline in yield and
eventually need to be replaced.
At present there are no economic ways to eradicate Phylloxera from
the soil and there is no treatment for infected vines except their
replacement with vines grafted onto Phylloxera resistant rootstock.
|
