Fuzzy Balls on a Hackberry Tree

I recently came across a real mystery in the most beautiful back yard I've ever seen.
Fuzzy infestation on the underside of leaves...

Not wooly aphids, not Hackberry Gall Psyllids, not  hackberry nipplegall maker but kinda...

Is there such a thing as a "wooly hackberry nipplegall maker"?

--more research---

I found this great article regarding treatment:

Treatment

While psyllid, scale and aphid infestations are most aggressive during the spring months, the hackberry can experience continuous infestations in climates that remain moderately warm throughout the year. Since the hackberry is rarely harmed by pest infestations and is always susceptible to these visitors, treat only severe infestations. To treat the infestation, use a horticultural oil-based insecticide spray. Apply the spray only on clear, warm days when there is no rain expected for at least 24 hours and no fog in the air. Spray the chemical thoroughly onto the hackberry’s foliage, stems and bark until the tree is saturated with the chemical. If the hackberry is severely infected, reapply the insecticide spray in 14 days. Treat the hackberry once per season to control the insect population and avoid infestations. If the hackberry tree experiences sooty mold infections as a result of the infestation, treat the infestation with the same horticultural insecticide. Feel free to prune away any ailing or blackened foliage.

---more research---nothing...

I had to ask the pro's at bugguide.com we'll see what they have to say about the strange infestation of fuzzy balls.

Closest thing I found... LINK

Weird fuzzy golf balls?  No, tiny galls on the underside of a shagbark hickory leaf.  Inside each gall is a tiny developing larvae of a fly or wasp, in this case a small fly.