Silver leaf, caused by the fungus Chondrostereum purpureum, is a wood rotting fungus that frequently attacks apple trees, particularly those that have undergone major tree surgery. The fungus has a wide host range including pear, stone fruit and many woodland, hedgerow and ornamental trees and shrubs. All apple varieties are susceptible.
The leaves of affected trees show the characteristic symptom. of a silver appearance. Whole trees or tree parts may be affected.
Once the tree or tree parts die, they become covered in fungal fruiting bodies which are 1.5-3 cm diameter brackets with smooth purple lower surface and pale brown hairy upper surface.
The life cycle involves the production of fruiting bodies on dead branches in autumn. Spores are released from these during wet weather from autumn to the following June and infect trees through wounds.
Apple trees showing symptoms of silver leaf may recover. Therefore, mark affected trees and monitor their progress. Grub immediately the tree dies and before fruiting bodies are produced.