Disease may hit half UK Horse Chestnut trees (Bleeding Canker)

A survey of more than 2,600 horse chestnuts across the country found that 49% showed symptoms of the bleeding canker disease, which attacks bark and can kill the tree or require it to be chopped down.

Previous estimates said only 5% of trees were affected. The symptoms were most common in south-east England, where more than three-quarters (76%) of the trees surveyed showed symptoms. Experts cannot be sure whether the trees have the disease until they are screened for the bacterium responsible; Pseudomonas syringae. The emergence of the bacterium has baffled scientists, because for decades the bleeding canker disease was thought to be caused by fungus.

This affects the horse chestnuts in Manchester too. Some have more natural resistance than others and there were less badly infected trees in parks last year, than the year before.

The trees will soon be coming into leaf though so now is a good time for everyone to be on the lookout for badly infected trees.

1. No leaves at all is obviously a bad sign.
2. Large limbs with no leaves will be dead and could fail without warning.
3. Stems with large areas of bark fallen off.
4. Small and/or yellow leaves on large areas of the crown are all causes for concern but do not indicate the tree’s imminent demise. These trees need to be noted and inspected on a very regular basis.

Unlike Dutch elm disease and the current Poplar Scab epidemic, were the diseased trees failed slowly and elegantly, the Horse Chestnuts may fail catastrophically – we all need to be alert.

If you notice any then contact Jo Walsh, Arboricultural Officer, Manchester Leisure, Alexandra Park Offices, 180 Russell Street, Whalley Range, Manchester, M16 7JL Telephone: 0161 226 3193, Fax: 0161 226 3348 or email using the form below.