Moved from Aphids. Elm, yes, and looks like the same aphids as your other photos. Several Eriosoma species spend part of the year on apple or other rosaceous trees and part of the year on elm.

Any chance you have photos that would tell us what kind of plant this was?

Psyllids (family Psyllidae) are related to aphids, but they often make "gall-like" structures like this. Some species secrete honeydew (like yours here) while others secrete little waxy, fibrous balls that will be inside the gall with them.

There are also related critters called adelgids (family Adelgidae) though they usually attack conifers most often, but they can also make gall-like structures and look similar, but at least you have a place to start.

When I get to work, I'll consult my references to see if there is any definitive way to tell whether you have psyliids here or adelgids. (I'm betting on the psyllids).


After looking at my references, I'm pretty sure that these are psyllids (family Psyllidae), now what kind of psyllids would be hard to tell without being able to look at the wing veination or knowing what host plant this is. Many psyllids are fairly host specific and will only feed on one type of plant or small group of plants.

I would guess this is a collection of aphids. When feeding, they have to continually excrete fluids as honeydew. Normally those drops just fall off the plant or are imbibed by ants and the like. Perhaps because these are enclosed the honeydew somehow forms into those balls?

Very mysterious. There seem to be at least two different kinds of creatures, plus several life stages. I hope that somebody tell us what all this is.