The gall wasp does not affect the long term health or vigour of the tree, but can affect its appearance.
- Collect and dispose of fallen leaves in spring as this will prevent some of the gall wasps completing their development
- On tall trees, control is not possible
- If the tree is small enough for the foliage to be sprayed thoroughly, a systemic insecticide such as thiacloprid (e.g. Bayer Provado Ultimate Bug Killer) or acetamiprid (e.g. Bug Clear Ultra) applied in spring may give some protection
Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)