What is it?
Mr. Bug Man,
Very cool website. Hope you can help. We have some Sumac trees in our backyard and some of them have these ‘sacks’ on them. They are attached to a leaf and seem to be feeding off of it. They are seemingly air tight, when you squeeze gently they are like a miniature air pillow. When taken apart there is a small cotton ball inside that is very air born and there are what look like seeds or eggs, yellowish in color, many of them. The sacks are various sizes and some are turning red like an apple would. Sure would appreciate your thoughts. Thank you,
These are Sumac Galls. According to BugGuide, the galls contain Aphid Colonies.