bud scale (Physokermes piceae) attacks mainly Norway spruce
but it will attack other spruces. This scale is small and is often
clustered in-groups of 3 to 8 at the base of new shoots. Their size
and color often allows them to be over looked or mistaken as buds.
They are round and reddish-brown in color. Lower branches are more
often attacked than higher branches. Severe infestations can produce
sufficient honeydew to develop so that sooty mold will grow. In
addition severe infestations can cause lower branches to die especially
on trees that are already weak or stressed. There is only one generation
per growing season. The immatures over-winter on the under side
of the needles. In the spring the females move onto the twigs to
complete their development. Crawlers usually appear in June.
Check with your local land grant university (Cooperative) Extension Service for recommended insecticide. Apply when hills-of-snow hydrangea is in bloom. Summer oils will turn blue spruces green.
Written by James Schuster, Extension Educator, Horticulture, and reviewed by Dr.Philip L. Nixon, Extension Specialist-Entomology, Department of Natural Resources and Environmental Sciences University of Illinois at Urbana-Champaign.