Horse Chestnut Tree Diseases: Warning Signs of a Sick Tree

A photo of a horse chestnut tree with healthy green leaves showing no signs of disease

To continue our series on warning signs that your tree might need a tree surgeon, we move on to the much-loved horse chestnut tree. Dotted throughout the English countryside and a staple feature of many heritage landscapes, sadly there are numerous horse chestnut tree diseases and pests that threaten its survival.

By learning to spot the warning signs that your horse chestnut tree might be sick, you can prevent further damage to either the tree or people and surrounding properties. Treesaw talk through the various horse chestnut tree diseases below and how to tell when your tree is under threat.


Bleeding Canker

One of the most severe threats to our horse chestnut trees, Bleeding Canker is a disease that has only existed in the UK since the 2000’s. Although experts advise it’s not spreading fast, there is still a worrying amount of our trees that now suffer from the disease.

Bleeding Canker is characterised by split bark that oozes a dark, sticky fluid. This dying bark then leads to a thinning of the tree crown. Many trees do die from Bleeding Canker, but some are seen to be surviving or avoiding the infection altogether. The advice is to consult a tree surgeon but aim not to chop the tree down unless absolutely necessary, as some trees can recover.


Horse Chestnut Leaf Miner

Originating in the UK around the same time as the Bleeding Canker, the Horse Chestnut Leaf Miner is thankfully not life threatening to the tree, but it can make the tree more susceptible to Bleeding Canker, which is life threatening.

The micro-moth has caterpillars that tunnel inside the very leaves of the tree in order to feed. This damages the leaves beyond repair, turning them brown and shriveled before they then prematurely fall. To tell that your horse chestnut has the leaf miner pest, look out for brown spots appearing on the leaf in early to late summer – far before the leaves should turn. You can sometimes even spot the caterpillars in the leaf by holding it up to the light, as the brown blotches are see-through.


Horse Chestnut Leaf Blotch

With very similar symptoms to the leaf miner, the two can often be mistaken. However, leaf blotch is a horse chestnut tree disease as opposed to a pest.

Similarly to the leaf miner, leaf blotch will turn patches of the horse chestnut leaves brown and cause them to shrivel completely if it is a severe case. You may also notice yellow edges on the leaves. This disease is not severe, but a tree surgeon should be consulted if spotted. The way to differentiate between the leaf blotch and the leaf miner is that with leaf blotch, the brown patches will not be see-through.

It is so important to do all we can to preserve our precious horse chestnut trees and prevent the spread of disease and pests where possible. If you’re concerned about the health of your horse chestnut tree or any other tree, don’t hesitate to contact the experts at Treesaw who can help you to protect your tree and property. Contact Treesaw tree surgeons today with any concerns you may have.