Symptom(s):

Various scales attack azaleas and rhododendrons, but one of the most common is azalea bark scale (Eriococcus azaleae). Scales are unusual insects. They vary in appearance depending on age, sex, and species. The adult female azalea bark scale is dark red with a long sucking mouthpart. It is hidden from view by the matted waxy threads of the egg sac that covers it. The egg sac is about 1/8 inch in length.

Cause(s):

Adult females are immobile and can usually be found feeding in the forks of branches and on twigs. The nymphs (immature forms called crawlers) move around for a short before they settle and start feeding. Both adults and crawlers suck plant sap.

Control(:)

A light infestation of scale can be scraped off the plant and discarded. Spraying with a dormant oil in early spring before new growth begins will kill some adults and eggs by smothering them. Insecticides are only effective against crawlers.  As with all pesticides, read and follow all label directions and precautions.