River birch leaves crinkled and discolored by aphid feeding.
If the leaves on your river birch look like this, do not be alarmed.
This distortion and discoloration is caused by a species of aphid
that only feeds on river birch and witch hazel. No treatment is
necessary -- the damage is temporary and not harmful to the plant,
plus the aphids will attract ladybugs and other beneficial insects
to your yard! Learn more: