This probably isn't a new pest, but it is new to me. Over the last few weeks, I've seen this pest at several nurseries in North and South Carolina.
Woolly Birch Aphid. This species, Hamamelistes spinosus, causes the leaves of River Birch (Betula nigra) to pucker and distort. Very cool.
NORMAL LEAVES:APHID-INFESTED LEAVES:
The distortion creates gall-like pockets where the aphids feed and reproduce.
Thankfully, the Woolly Birch Aphid only has one generation per year.
If you are a homeowner, the best course of action is no action at all. While the affected leaves cannot be cured, subsequent leaves that are formed will emerge without damage.
If you are a horticulturist and your trees have a history of this pest, you can apply a systemic insecticide at budbreak to prevent infestation and damage.