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Green spruce aphidOn this page: Identification & Distribution Other aphids on the same host
Identification & Distribution
Apterae of Elatobium abietinum are pale to dark green (see first picture below), sometimes with a partial wax bloom. The antennae are 0.45-0.55 times the body length, with the terminal process 1.0-1.6 times the length of the base of antennal segment VI. The hairs on segment III are 0.25-0.33 times the basal diameter of that segment. The rostrum reaches to behind the hind coxae, with the apical rostral segment 1.0-1.2 times the second hind tarsal segment. Marginal tubercles are absent. The siphunculi are pale, thin, cylindrical, 1.9-2.5 times the length of the cauda, and tend to be slightly s-curved (cf. various Cinara species on Picea which have the siphunculi on broad pigmented cones). The cauda is pale and pointed, with 5-7 hairs. The body length of Elatobium abietinum apterae is 1.0-2.0 mm.
Second image above copyright Volker Fäßler, all rights reserved.
The alate Elatobium abietinum (see second picture above) is green with intersegmental muscle sclerites. The antennae, tarsi and tips of tibiae are somewhat darker. The antennae are 0.6-0.7 times the body length, and segment III bears 3-16 secondary rhinaria irregularly distributed along one side.
Elatobium abietinum spend all year on the needles of spruce, especially Sitka spruce (Picea sitchensis) and Norway spruce (Picea abies) and, much less commonly fir (Abies species). The green spruce aphid has an unusual life cycle in that populations often continue to feed and reproduce through the winter. In spring and early summer alates are produced in response to the changing nutritional status of the host. They then migrate to other spruce where their nymphs aestivate for the summer before resuming development in autumn. Elatobium abietinum can be a serious forestry pest with colonies on spruce causing discoloration and loss of old needles (see pictures below), sometimes causing serious defoliation.
The species is native to Europe, but it has now spread to Australia, New Zealand, Chile and North America. Populations in continental Europe have a sexual stage, but elsewhere overwintering is by parthenogenetic forms.
Other aphids on same host:
Elatobium abietinum has been recorded on 14 Picea species - and at least 5 Abies species (Abies cephalonica, Abies coerulea, Abies homolepis, Abies kosteri, Abies lasiocarpa).
Blackman & Eastop list about 170 species of aphids as feeding on spruces (Picea) worldwide, and provide formal identification keys.