Horse Chestnut bleeding canker

Scientifically referred to as Pseudomonas syringae pv. Aesculin, Horse chestnut bleeding canker is a bacterial canker that causes bleeding from the bark on any part of the trunk or main branches of the tree.  The bacteria multiply within the water transport system of the tree just under the bark, eventually blocking them.  This can cause the tree to die if it can no longer transport the water.  The disease is specific to the common Horse chestnut and Red Horse chestnut.

Trees of all ages can be affected with some infections lasting for years with little impact on the crown, while some spread rapidly and cause crown thinning, dieback, and sometimes death of part of or even the whole tree.

Symptoms include:

• Cracks in the bark which ooze a dark or reddish-brown sticky liquid where the infections occur. In dry weather, this dries out to form a rusty-brown or black deposit
• Discoloured wood under the bark. Healthy inner bark is a white or pinkish colour whereas an infected tree will have patches of brown or purple discolouration.
• On old cankers, the dead bark may fall away to expose the wood