From UMass Amherst:

"Management Strategies:
Eggs hatch around 80 growing degree days. The adults will begin to appear around 300 growing degree days. Given that the eggs are well protected within the bud scales, horticultural oils are usually not effective in managing this life stage. Once leaf cupping occurs, the nymphs are also somewhat protected from oil sprays and insecticidal soaps. Several chemical pesticides are labeled for this pest. Injury is primarily aesthetic and, given the setting, no management intervention may be necessary."

If you don't mind the appearance of the pest, just leave it alone. It doesn't look like there is a reasonable non-synthetic control.

Steve

Here is a link that might be useful: Boxwood Psyllid - UMass

I just take off all the cupped leaves when I prune. One of these years, I'd like to start early and continue to prune off every time there is new growth and see if that would diminish the infestation.

A good clipping might just be in order!

Thanks for the responses.