Always, the infested twigs are covered with tiny white scales. With a hand lens, one can see the volcano shaped female scales, oblong males and yellow specks which are the scale crawlers. Pesticides are best applied to the vulnerable crawlers. Aphids on juniper seem more of a problem during the growing season. Sometimes ants, pirating the honeydew, or ladybeetles are more noticeable than the black aphids themselves.
Aphids can devitalize the plant or branches if they are abundant.
Juniper webworm is a caterpillar that makes messy nests of webbing, dead needles and grass. The striped, brownish caterpillar is well hidden among the mess it makes. This pest is rare in our area. Parasites or natural predators seem to control it well. The adult is a small moth.