About flavescence dorée of grapevine
Flavesence dorée of grapevine is a phytoplasma (type of bacteria) that causes disease in grapevines. The disease gets its name from the yellowing of the leaves. It is found inside the sugar transport system (phloem) of grapevines and in some species of leafhopper insect.
The disease is found in several European countries where grapes are grown.
Global distribution of flavescence dorée of grapevine
Why this is a problem for New Zealand
The flavescence dorée disease could cause great economic losses to the wine industry. It reduces growth and crop yield. The quality and quantity of grapes can be significantly reduced.
Some grape types (cultivars) are more susceptible than others. In Europe, many of the main wine growing varieties seem to be affected.
How it could get here
The disease can only be transmitted to healthy plants by grafting from infected plants or through a carrier insect (vector). It can move great distances with infected plant material or insects.
New Zealand doesn't yet have any of the important insect vectors.
Biosecurity New Zealand strives to keep New Zealand free of this disease in a number of ways. We quarantine and test any imported grapevine nursery stock. We also have strict measures to limit the chances of the insect vector arriving.
How to identify flavescence dorée
You would probably first notice its presence in early summer on a few shoots only. It can take several years for symptoms to show and they can be confused with other diseases.
Disease symptoms include:
- stunted buds or lack of bud break
- yellowing or reddening of leaves with curled edges
- woody canes that ripen poorly and stay rubbery
- shrivelled or wilted flowers and berries.
If you think you've found flavescence dorée
Experienced vineyard workers who've found unusual symptoms that match this disease should:
- photograph the plant
- call 0800 80 99 66
Note: This information is a summary of this disease's global distribution and potential impacts on New Zealand.