Crapemyrtle Bark Scale is becoming a widespread pest in Maryland, but there are treatment methods, though they usually involve insecticide (low-toxicity or otherwise). Physical removal using a soft scrub brush may be tedious, but will help reduce the amount of pesticide needed, and might speed-up results from treatment, which otherwise might need to take over a year if scale populations are large enough. Information about the life cycle of this scale, which is still being studied in Maryland since it's fairly new, and which impacts when certain treatments are applied, can be found on the linked page and the "management" section of the general scale insect page.

Miri