Xylella fastidiosa is a damaging bacterium whose symptoms include leaf scorch, wilt, dieback and plant death. It has caused significant mortality to olive trees in southern Italy and has been found on ornamental plants in Corsica, southern France, Germany and Spain. X. fastidiosa is transmitted by insects such as spittlebugs.
If found in the UK, Xylella could have devastating consequences on horticulture. EU control methods include destroying all host plants within 100m (328ft) of any find, and a movement ban for plants within a 6 mile radius for up to five years.
Xylella fastidiosa has over 350 potential hosts, including common garden plants such as lavender, rosemary, wallflower, grape vine, plum and cherry trees or sycamore. A full list is available here.
In order to minimize the risks of introducing Xylella in the UK, the Royal Horticultural Society has issued new guidelines regarding the use of host plants at RHS shows. The following plants :
- Coffea spp. (coffee)
- Hebe spp. (hebe)
- Lavandula spp. (lavender)
- Nerium oleander (oleander)
- Olea europaea (olive)
- Polygala myrtifolia (polygala)
- Prunus spp. (cherry, plum etc.)
- Rosmarinus officinalis (rosemary)
- Spartium junceum (Spanish broom)
will only be allowed for display at RHS shows if they have been propagated from seed in the UK or have been grown in the UK for a minimum of 12 months preceding the Show.
As Collection Holders, if you are importing plants from Europe, please make sure to follow appropriate biosecurity measures such as quarantine, record keeping and good hygiene.