Galls: Identifying Characteristics
| Identifying the stress: | Galls vary greatly in size, color, and texture depending on the type of insect causing the gall. It is often possible to identify the gall-causing insect based on the type and appearance of the gall. Where the gall is located on the tree is also very important in determining the cause. Galls can form on any part of a tree or shrub and there may be numerous galls on a single plant and plant part. Look for any swollen abnormality. |
| Susceptible trees: | Any tree can produce galls, although oaks are often favorite hosts. |