Introduced into Europe during World War 2 on munition boxes from the eastern United States, it rapidly spread through Italy and Switzerland but until recent years the spread was slow through France.
There are 42,000 Plane trees along the Canal du Midi in France, a unesco world heritage site, it is feared they may all have to be felled and destroyed due to the disease, this will take several years to achieve.
Although not present in the Uk if it were to accidentally be introduced the streets of London could look very different.
Cause
The ascomycete fungus Ceratocystis fimbriata f. platani (a Wilt pathogen), usually spread by human activity, pruning or other tree works.
Symptoms
Small leaves, sparse foliage, Leaf wilt or complete defoliation.
Staining.
Elongated sunken cankers on the trunk or large branches, these may appear to be flat, darkened areas, these may become rough with age.
Beneath the bark these cankers may have blueish/black colour.
Infected trees will usually die within 3-7 years.
There is no chemical available to effectively control the disease. As the disease it thought to be spread more through human activity, as opposed to sap eating feeding insects, then good arboricultural practices could certainly help to lesson the spread. Any pruning equipment should be disinfected after use, any possible contaminated soil should be disposed of, infected cuttings should be burnt and any trees found to have the disease should be destroyed.
In order to import Platanus hispanica you must have a plant passport, all imports must be notified to the UK plant health authorities so inspections can be carried out.
Ceroatocystis fimbriata f. platani is also listed on the UK Plant Health Risk Register.
For more information on Plane tree wilt please visit Forestry.gov