Family Adelgidae 
Adelgids 
Members of this family differ morphologically from true aphids 1n having shorter 
antennal segments and lacking cornicles. Unlike the Aphididae, both sexually 
perfect and imperfect female adelgids lay eggs. All species occur only on conifers. 
Feeding sites of important eastern adelgids include needles, twigs, limbs, trunks, or 
the inside of galls. 
The eastern spruce gall adelgid, Ade/lges abietis (L.), an introduced species 
from Europe, occurs in southeastern Canada and in the Northeastern and Lake 
States. Its preferred host appears to be Norway spruce, but it is also found 
occasionally on white, red, and blue spruces. [t overwinters as small nymphs under 
coverings of waxy threads at the bases of buds on the undersides of twigs (/290). 
The nymphs molt in the spring and become stem-mothers that lay eggs on the 
needles about the time the buds are ready to break. Hatching occurs in about 2 
weeks and the young nymphs crawl to the bases of new needles. Here they feed, 
causing the formation of pineapple-shaped galls (958) in which they live and 
continue their development (fig. 25). During late August to October, the galls open 
and the nearly mature nymphs craw] out onto the needles. The nymphs transform to 
winged adults in a couple of days but, because they are weak fliers, many remain on 
the tree. The females insert their mouth parts through the bark, deposit 100 or more 
eggs each, and then die. These eggs hatch within 16 days and the young nymphs 
immediately crawl to overwintering sites. There is one generation per year. This 
insect is a serious pest in nurseries and Christmas tree plantations and on park and 
Courtesy D. C. Allen, 
SUNY, Coll. Environ. Sci. & For. 
Figure 25.—Galls of the eastern spruce gall adelgia, 
Adelges abietis, on spruce. 
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