Galls

Tree affected by galls

What is a gall?

Galls are malformations that develop on leaves, branches or roots. Galls are caused by nematodes, mites or insects, and to a lesser extent, by bacteria, fungi or viruses. Many galls are very different, depending on the plant material and the gall producer. For that reason, sometimes the organism making the gall can be identified using the shape and colour of the gall.

What kind of damage is caused by galls?

Galls on trees can modify the shape of the affected tissue but typically not affect the health of the tree.

How do I control galls?

Galls on trees typically do not require any treatment.