Pine needle scale, Chionaspis pinifoliae, is an insect pest native to the U.S. that feeds on pine trees grown in ornamental nurseries, landscapes, and Christmas tree plantations, including Scots pine, Pinus sylvestris and mugo pine, P. mugo. Pine needle scale will also feed on Austrian pine, P. nigra, red pine, P. resinosa, and occasionally feed on fir, Abies spp. and spruce Picea spp. trees. This publication provides information on pest biology and plant damage, and management strategies that can be used to prevent damage caused by pine needle scale.

Biology: Adult pine needle scale females are ⅛ inches (3.0 mm) long and white with an orange portion that tapers at one end (Figures 1 and 2). Males are white with a rectangular covering about ¹/₂₅ inch (1.0 mm) long. The males develop into winged individuals, mate with females, and then die. Mated females produce a white, waxy covering that provides protection from exposure to insecticide sprays. The females lay (oviposit) red eggs underneath the protective covering, and then die. Each pine needle scale female can produce up to 100 eggs. Red nymphs (crawlers) emerge (eclose) from the eggs and crawl out from under the covering of the dead female. First-generation nymphs emerge over a 2-3 week period in spring, moving to pine needles to feed on current growth or pine needle growth from the previous year. A second generation of nymphs emerges in the summer. The firstinstar nymphs are flat, narrow, and red, and after molting, become second-instar nymphs that are yellow to lightorange (Figure 3). The developmental stage of an insect between molts is an instar. After 6-8 weeks, pine needle scale nymphs become mature adults.

Pine needle scale nymphs are dispersed by wind or carried by birds to new locations where they can infest other trees. Pine needle scale also moves onto branches of adjacent trees that are touching. Pine needle scale overwinters as red eggs underneath the dead female’s covering. There are two generations per year in Kansas.

Damage: Pine needle scales withdraw plant fluids from the inner tissues (mesophyll layer) of pine needles using their piercing-sucking mouthparts. Feeding causes pine needles to turn yellow and fall from trees, beginning with the lower branches. Pine needle scale feeding can affect the appearance and marketability of pine trees grown for Christmas trees, and reduces the growth and vigor of pine trees grown in nurseries and landscapes. Heavy infestations of mature pine needle scale appear as white flecks on needles.