Aphids

Albrecht, Anders Christian, 2017, Illustrated identification guide to the Nordic aphids feeding on Conifers (Pinophyta) (Insecta, Hemiptera, Sternorhyncha, Aphidomorpha), European Journal of Taxonomy 338, pp. 1-160 : 27-28

Key D. Aphids on hemlock and Douglas fir ( Tsuga and Pseudotsuga )

Synopsis

D1 (D4) On young shoots or needles ..............................................................................................D2

D2 (D3) Siphunculi absent ............................ Adelges Vallot, 1836 and Mindarus Koch, 1857 p. 28

D3 (D2) Siphunculi present, tubular........................................................ Aphis Linnaeus, 1758 p. 29

D4 (D1) On thin mycorrhizal roots ............................................ Eriosomatinae Kirkaldy, 1905 p.29 D1 (D4) On young shoots or needles ..............................................................................................D2

D2 (D3) Siphunculi absent ..................................... Adelges Vallot, 1836 and Mindarus Koch, 1857