Flavescence dorée

Grapevine flavescence dorée MLO

1. Identification

Grapevine flavescence dorée is a serious disease caused by a phytoplasma, known internationally as “Grapevine flavescence dorée”, or “Flavescência Dourada da Videira” in Portuguese. It is a quarantine disease in Europe, with a strong impact on viticulture.

2. Causal agent

A phytoplasma belonging to the 16SrV group, designated as “Candidatus Phytoplasma vitis”, described by Lee et al. Phytoplasmas are bacteria without a cell wall, restricted to the phloem, transmitted by insect vectors.

3. Main hosts

• Grapevine — highly susceptible
• Some wild Vitis species can act as reservoirs
• Spontaneous herbaceous plants can harbour the phytoplasma without symptoms

4. Symptoms

• Yellowing (white varieties) or reddening (red varieties) of the leaves
• Downward leaf curling
• Failure of lignification of the canes
• Withered berries, dropping of bunches and total loss of production
• Progressive decline of the plant and death in severe cases

5. Disease cycle

The phytoplasma is transmitted mainly by the insect vector Scaphoideus titanus, which acquires the pathogen by feeding on infected plants. After a latency period in the insect, the phytoplasma multiplies and is then transmitted to new plants during feeding. The disease is not transmitted by seeds, but is easily transmitted by infected vegetative material (rootstocks, scions, cuttings).

6. Favourable conditions

• Presence and high density of the vector S. titanus
• Hot summers that favour the development of the insect
• Use of non-certified propagation material
• Abandoned or poorly managed vineyards that act as infection foci

7. Disease management

• Certified plant material: avoid introducing the phytoplasma into the vineyard
• Vector control: phytosanitary treatments mandatory in many European regions
• Removal of infected plants: immediate elimination to reduce sources of inoculum
• Management of spontaneous vegetation: reduce alternative hosts
• Monitoring: regular inspections during summer and early autumn
• Regulatory measures: compliance with national and European phytosanitary standards

Bibliographic references

• EPPO. Diagnostic Protocol PM 7/079: Flavescence dorée phytoplasma.
• Boudon-Padieu, E. (2003). Flavescence dorée of grapevine: knowledge and new developments.
• European Food Safety Authority (EFSA). Pest categorisation of Grapevine flavescence dorée phytoplasma.
• Bertaccini, A., & Duduk, B. (2009). Phytoplasma and phytoplasma diseases: a review.