A fungal infection mainly of the Prunus genus, though it occasionally attacks other trees. The disease, which is most frequently encountered with plums, is recognised by a silvery sheen on the leaves.
Initially only one branch may be affected. The fungal spores enter through cuts and abrasions. The diseased wood is stained brown, and in the autumn flat, brown, bracket-shaped fruiting heads appear on infected trunks and branches.
If prompt action is taken, it is sometimes possible to save the tree.
As soon as the disease is noticed on the leaves, cut back the infected branch until the exposed stem is no longer brown in colour.
Often the most practical way of doing this is to cut back to the point where it emerges from the leader.
All diseased wood must be destroyed by burning.
If fruiting heads appear on the main trunk, the whole tree must be dug out, including the roots, and destroyed.