Explanation of Names
Adelges (Dreyfusia) piceae (Ratzeburg)
piceae = 'of spruce' (NB: spruce is not a host for this species!)
Purple to black. As they mature, they cover themselves with cottony white wax, and become much more noticeable. Adults are near-spherical and usually wingless.
Non-native; established throughout w. & e. NA
Anywhere with fir trees, including Christmas tree farms
In most of range, only one immature life stage survives the winter; adults and other immature life stages occur from spring to fall. In the South, all life stages occur year-round.
True firs, especially balsam fir (Abies balsamea) and Fraser fir (A. fraseri). Feeding takes place on rough areas of bark (lenticles), branch nodes (where a new twig would grow), and under cone-forming buds.
A substance injected by the aphid causes abnormal cell growth, can stunt tree growth, prevent cone/seed formation, and eventually kill it.
2-4 generations per year, depending on climate and elevation; all individuals are female and reproduce asexually
Masses of 200-300 tiny eggs hatch into nymphs called "crawlers," which seek out feeding locations and insert their mouthparts under the bark. They then lose their legs, develop a waxy white fringe, and remain stationary as they mature. Adults cover themselves with thick cottony wax and lay eggs under this protective covering.
Most adults are wingless and stationary, but winged adults may occur in the Maritime Provinces.
Accidentally introduced from Europe to ne. US and se. Canada in the early 1900's, the West Coast in 1929, and the southeastern US in the 1950's. The population established in eastern North America may have contributed to the later introductions.
Most North American firs are very sensitive to feeding damage, but a few species show natural resistance: white fir, noble fir, and Shasta fir.
Hemlock Woolly Adelgid (Adelges tsugae) - almost always on hemlock; feeds on new growth and needles, not branches or tree trunks; adults have wings and are mobile.
Ragenovich I., Mitchell R. Revised 2006. "Forest Insect and Disease Leaflet 118: Balsam Woolly Adelgid." USDA Forest Service. Available online: http://na.fs.fed.us/pubs/fidls/bwa.pdf
Insects and Diseases of Trees in the South." 1989. USDA Forest Service - Forest Health Protection. R8-PR16.