Advice on management of bleeding canker of horse chestnut

 

Summary

Confirming exactly what agents are causing horse chestnut bleeding canker is critical to any recommendations about effective control measures. Before embarking on any control measures on sites where there is a significant number of horse chestnuts, a survey to assess the number of affected trees is recommended.

There is no chemical treatment currently available to cure or arrest the development of bleeding canker:

• If the lesions become so extensive that the entire trunk is girdled, the tree will inevitably die and have to be removed and disposed of appropriately.
• If major branches are infected and show dieback they should be removed, because recently-dead branches of horse chestnut may be susceptible to sudden fracture and drop as the wood dries out.

Advice on the best time of year to prune is given in Arboriculture Note 117 (Lonsdale, 1993).  However, many trees with trunk infections retain healthy-looking crowns and may not pose an immediate safety risk. Some may even survive for many years as disease progression can be very slow or even cease, and show signs of recovery as vigorous callus development occurs at the margins of wounds created when bark has been killed by the disease.

Detailed information

• Specific recommendations
• Surveying
• Disposal of infected material
• Replanting