The pine needle scale appears as a white speck about 1/8 in.
in length with a yellow to brown spot at one end. The insect
itself is purplish while the eggs and crawlers are both red.
Male scales are winged and capable of flight. Female scales
are wingless. In winter, the scale will appear gray with purplish
eggs underneath the waxy covering. Heavily infested trees
have a white or "flocked" appearance. Austrian and
mugho pines are favorite hosts of the scale however, Scots
and red pines as well as some spruces may be attacked.
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Figure 1. Pine Needle Scale
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Figure 2. Pine Needle Scale on Scots Pine
The pine needle scale overwinters as an purplish to reddish
egg underneath the parent scale. From 20-30 eggs may overwinter
under each female. The eggs hatch in May or June into active
crawlers. The crawlers move around on the foliage for a few
days, then insert their beak into the leaf tissue, and begin
secreting the waxy covering. By late summer they are full
grown. A second generation may appear in August. Scales mature
and the female deposits eggs which overwinter. There are two
generations per year.
Trees infested with pine needle scale are less vigorous and thrifty
and have yellowish to brown needles. The marketability of the tree
is reduced particularly those used for Christmas trees. Heavily
infested trees may experience needle drop or dieback of branches.
Heavy infestations can lead to the death of the plant.
Various parasites and predators have been recorded from the pine
needle scale and undoubtedly aid in controlling populations.
Control of the pine needle scale may be achieved by applying a crawler
spray in late May. Dormant oil sprays may also be effective in controlling
the overwintering eggs.