I thought those are scale specific to rhodos and azaleas, so I looked them up.
See if these fit --
Thin azaleas with crusty stems may have azalea bark scale | MSU Extension
https://msue.anr.msu.edu/news/thin_azale ... bark_scale
look for a crusty covering of scale insects on the stems, or white, waxy egg masses produced by the females (see photos). Infested stems and leaves under infested stems may also turn black from the black, sooty mold fungus that grows on the sugary liquid waste excreted by the scale insects.
As mentioned here, I would start by just picking off scattered infestation -- rubbing alcohol+light oil like canola mix on cotton swabs or bamboo chopstick scored and wrapped with cotton (I use the vitamin jar cotton) -- and cutting off heavily infested branches. Though you may still end up needing to spray, I prefer to leave as last resort because these sprays will also kill their natural predators.
HGIC 2051 Azalea & Rhododendron Insect Pests : Extension : Clemson University : South Carolina
https://www.clemson.edu/extension/hgic/p ... c2051.html
Control: A light infestation of scale can be scraped off the plant and discarded, or heavily infested branches may be pruned out. A horticultural oil spray applied in early spring before new foliar growth begins will kill many over-wintering adults and eggs by smothering them. Spraying horticultural oil during the growing season will help control crawlers, as well as adults and eggs. Apply horticultural oil sprays at a 2% solution (5 tablespoons oil per gallon of water). Spray the plants thoroughly, so that the oil spray drips or "runs off" from the upper and under sides of leaves, twigs, and plant stems.