Stimmel, J.F. 1996 Spruce bud scale, Physokermes hemicryphus (Dalman) (Homoptera: Coccidae).. Regulatory Horticulture (Pennsylvania Department of Agriculture) 22: 9-11.

Notes: This European introduction into the U.S. has spread throughout the northeast, the upper midwest (Wisconsin), and the northwest; identification; life history; description of damage; control measures.