page_title: Pineapple gall adelgid
section_title: Life-cycle
hierarchical_section_title: Pineapple gall adelgid / Life-cycle
caption_attribution_description: English: A Pineapple Gall on Sitka Spruce, Redhall, Edinburgh.
context_page_description: 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. Adelges abietis is one of the most common species; synonyms are A. gallarum-abietis, Chermes abietis and Sacciphantes abietis.
  The pineapple or pseudocone gall is a type of insect-formed gall, or abnormal outgrowth of plant tissue, that develops as a chemically induced distortion of needles, observed mostly on Norway spruce and Sitka spruce.
context_section_description: Only females of the pineapple gall adelgid are known. In spring, the newly hatched nymphs formed from over-wintered eggs feed at the bases of the growing needles; the induced swellings eventually coalesce to form the pseudocone structure, each cell of which contains about twelve nymphs. The nymphs overwinter under wax threads at the base of buds. They die shortly afterwards, leaving the eggs, which resemble white, cottony twigs, protected beneath their bodies.
  In late summer (July–September) the fully developed nymphs emerge from the galls and crawl out onto the needles, where they molt and develop wings. These adult adelgids may fly to other susceptible conifers, such as larch (Larix), pine (Pinus) and silver fir (Abies alba) or may continue the cycle on the same tree, as some are poor flyers. Several generations are raised on these secondary hosts, however no galls are formed. In July of the following year winged adelgid appear and fly to the spruces to breed there again, completing the life cycle.
caption: Pseudocone on Sitka Spruce.
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