Plane wilt (Ceratocystis platani)

What does plane wilt look like?

Symptoms include:

• A sudden wilting of the leaves appears as the pathogen blocks up the water transport systems of the tree. Often wilting just occurs on one branch and then spreads.
• Sparse, thin crown with yellowing leaves.
• Canker stain marks on the bark. These are sunken lesions with orange and purple streaking around the edge.

What is plane wilt and what happens to the tree?

It is a wound parasite; a pathogen that enters the tree via existing cuts and damage. When the soft outer layers of wood underneath the bark are infected, vessels in the vascular system are blocked from transporting water and energy and cause the sudden wilting of the tree.

How did plane wilt get here and what impact will it have?

Plane wilt is not present in the UK. The pathogen was accidentally introduced from the eastern United States through a number of southern European ports during World War II on infected crates. It spread rapidly through Italy and into Switzerland and France.

The disease is always fatal to the tree. Smaller trees tend to die off more quickly than mature trees.

There is no way of controlling the disease with chemicals but in Europe plane trees are being developed that show resistance to the pathogen.

What are we doing about it?

Imported live plants and wood is the biggest risk for plane wilt entering the UK. The UK is now a protected zone for plane wilt and the movement of plane to the UK is banned unless they have been grown in an area free of the disease.

To combat the spread of pests and diseases like plane wilt we have:

• Developed a UK and Ireland sourced and grown assurance scheme to make sure that all the trees we plant and sell are produced in the UK. 
• Lobbied the government to improve biosecurity at border points to stop new pests and diseases entering the UK.
• Partnered with Observatree, a tree health citizen science project which trains volunteers to spot pests and diseases, thereby helping tree health authorities identify and manage outbreaks early.

What to do if you spot it

If you think you've spotted the signs and symptoms of plane wilt you need to report it to the plant health authorities via TreeAlert if you are in Britain or TreeCheck if you are in Northern Ireland.