Here is another great photo that was sent into me this week. This aphid is known as the beech blight aphid and it is one of several woolly aphids commonly encountered throughout North Carolina.
The aphids first become apparent in early August and as populations continue to grow they become increasingly noticeable. Very high numbers can be seen on individual branches, sometimes extending onto leaves, with lots of sooty mold built up below. They do not usually cause much damage to overall tree health, but we occasionally see dieback on very heavily infested branches.
However, this aphid does exhibit a curious response to potential predators. When disturbed, the entire colony will raise their "cottony" abdomens, and begin wagging these fluffy derrieres in unison at the aggressor.
See the video below for an example if this "boogie-like" behavior on video from youtube.
Beech Blight Aphid