As the swelling expands it cuts off the water supply to the main trunk or branch, causing the death of the branch. A canker infection mimics the die back associated with the bronze birch borer. Cankers in branches may be removed by proper pruning. Just as with the bronze birch borer, control is in maintaining proper tree health. Any pest of a tree that is not lethal or disfiguring can be considered minor.
Birch trees have a number of minor pests.
The least significant is the paper wasp which will peels a strip of bark causing a few twigs to die back. Spittle bugs and aphids do more damage than wasps but are still minor. Both insects are sap feeders and will cause leaf loss. Spittle bugs protect themselves in a frothy spittle. Aphids are often found in large numbers under leaves.