Pineapple gall adelgid

Adelges abietis

The Pineapple gall adelgid is a type of conifer-feeding insect that forms pineapple-shaped plant galls on its host species, commonly Norway and Sitka spruce. The adelgids are pear-shaped, soft-bodied green insects with long antennae, closely related to the aphid. "Adelges" lays up to one hundred eggs at a time, one on each needle.
Pineapple Gall - Adelges abietis Adelgids overwinter as nymphs on twigs near the terminal buds. They mature around early May and lay their eggs, which hatch in about a week. The young insects then begin to feed on the buds that had been fed on by the overwintering nymphs previously. This feeding induces abnormal growth of plant cells and the progressive enlargement at the bases of infected needles. Eventually, the enlarging needles coalesce and form a characteristic pineapple-shaped gall within which the insect lives and grows. The galls split and the mature adelgids emerge, develop wings, fly to the needles of the same or some other spruce where lay eggs at the base of the new growth. The eggs soon hatch and the immature forms that emerge will feed until the onset of cold weather, overwinter at the needle bases and then resume their life cycle the following spring. Oddly, only females of this adelgid are known to occur. Habitat: Spruce (Picea sp.); mixed forest Adelges,Adelges abietis,Geotagged,Picea,Pineapple gall adelgid,Spring,United States,adelgid,gall,spruce,spruce gall

Appearance

The gall is formed from the swelling of the bases of the needles punctured by the feeding activity and activated by the saliva of the insect. The unilarval chambers are set in a woody core. The stem and needles of the host can continue growing beyond the position of the gall.

Sitka and Norway spruce are the main hosts, but ''A. abietis'' galls can be found on Colorado blue, white, and red spruces.

The yellowish green galls pass through pink and then reddish-brown colour phases. On average, they measure 1.5 to 3.0 cm in length.

Similar galls are produced by other aphids: on Sitka spruce, by the Cooley spruce gall adelgid, ''Gilletteela cooleyi'', some generations of which migrate to Douglas fir ; and on spruce by ''Cnaphalodes sp''., which is heteroecious with larch. The Cooley spruce gall adelgids form a larger gall, 1 to 3 inches long, which usually covers the entire tip of infested new growth.
Pineapple Gall - Adelges abietis Adelgids overwinter as nymphs on twigs near the terminal buds. They mature around early May and lay their eggs, which hatch in about a week. The young insects then begin to feed on the buds that had been fed on by the overwintering nymphs previously. This feeding induces abnormal growth of plant cells and the progressive enlargement at the bases of infected needles. Eventually, the enlarging needles coalesce and form a characteristic pineapple-shaped gall within which the insect lives and grows. The galls split and the mature adelgids emerge, develop wings, fly to the needles of the same or some other spruce where lay eggs at the base of the new growth. The eggs soon hatch and the immature forms that emerge will feed until the onset of cold weather, overwinter at the needle bases and then resume their life cycle the following spring. Oddly, only females of this adelgid are known to occur. Habitat: White spruce (Picea glauca). This poor tree tree was covered in galls. Adelges,Adelges abietis,Geotagged,Pineapple gall adelgid,Spring,United States,gall,pineapple adelgid

Distribution

Prominent in appearance, the pineapple or pseudocone gall is often confused with the actual cone of the tree, due to their superficial resemblance. Pineapple galls are distinguishable by their small size, position on the base of budding twigs, and habit of the branch growing on and extending past the gall.

The pineapple gall adelgid is endemic to Europe, belonging to the 'woolly adelgid' group; it is also widely distributed in the north-eastern United States. Spruce gall aphid, eastern spruce pineapple gall adelges and eastern spruce gall aphid are alternative names. This insect belongs to the superfamily Aphidoidea, and family Adelgidae. It is the primary pest of Norway Spruce. Another similar species, the Cooley spruce gall adelgid, is indigenous to North America. This adelgid usually affects Colorado Blue, Sitka, Englemann, and Oriental spruces.

The eastern spruce gall adelgid is an introduced species that feeds only on spruce. At least in 1985, the species was found in Canada from Ontario eastward and in adjacent parts of the United States.

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Taxonomy
KingdomAnimalia
DivisionArthropoda
ClassInsecta
OrderHemiptera
FamilyAdelgidae
GenusAdelges
SpeciesA. abietis
Photographed in
United States of America