Birch leafminer is a type of sawfly which originated in Europe and closely related to bees and wasps. The sawfly attacks all types of birch trees. Signs of the pest can be seen in the damage – translucent brown blotches on leaves.
In addition to being unsightly, the damage caused by birch treeminer can cause stress in a birch tree, thereby becoming a possible factor in weakening the tree and making it more susceptible to even serious problems such as bronze birch borer.
The leaves of the birch tree will be eaten. Early signs are brown translucent blotches on the leaves. The small sawflies are visible. Leaves will often brown early in the season.