- Bizarre structures develop an oak's foliage, buds and
acorns. This will happen mainly in late summer but some develop in
the spring. There are more than 30 species of gall wasps in Britain
on the common oak. Each species lays its eggs in a particular
structure on the tree - the roots, bark, buds, leaves, catkins or
acorns. Chemicals secreted by the wasp grub alter the normal cell
division process and cause the plant to produce gall tissues that
enclose the grubs. These vary in shape and size.
To view care instructions for this problem please login or register.
Discuss Oak galls with other Shoot members.
Login or register to add a comment or question about this plant problem.