Spruce Bud Scale – Physokermes piceae

Spruce Bud Scale – Physokermespiceae

Common Name: Spruce Bud Scale

Latin Name: Physokermespiceae


The spruce bud scale is spherical and reddish-brown. Female mature scales are around 3mm in diameter and coated in finely powdered wax. They are found in colonies of three to eight individuals near the base of new growth, usually on the lower branches. Female mature scales are similar to spruce buds and may be partially obscured by the bark. Honeydew is produced by spruce bud scales, which become coated with black sooty mold. Previously, an imported bud scale was misidentified as the spruce bud scale. It was only recently that P. hemicryphus was recognized as a distinct species.

Host plant: 

The spruce bud scale mostly infects spruce trees, with black spruce, Norway spruce, White spruce, and red spruce being its primary hosts. Some pines have also been identified as hosts. Because the spruce bud scale targets attractive plants, it is commonly seen in nurseries.


Spruce Bud Scales are found throughout Canada and United States

Damages caused by Spruce Bud Scale

The spruce bud scale wreaks havoc on spruce trees by draining sap from the shoots. The scaled colonies exude a lot of honeydew, eventually turning into black mold. Mold plugs the pores of the tree, preventing gas exchange. Heavy infestations turn the trees black, causing weakening and increased vulnerability to disease causes, particularly winter dryness. Because the lower branches are more susceptible to infection, they may grow ragged and even die. Although heavily afflicted spruces may have diminished vigor and development, the infection seldom kills the entire tree.

Life history and habits:

Each year, one generation is born. Immature scales overwinter on the undersides of needles near the base of the terminal and lateral buds. The scales reach maturity in late June. Each female produces a hundred or more violet eggs beneath her body, which is a protective coating. They emerge from under the parent scale in late July. Flat nymphs, sometimes known as crawlers, land on new growth and begin feeding. From late June to early August, crawlers actively eat by inserting their feeding tubes and sucking the fluids from the needles.