Aphis pomi and Aphis spiraecola, are both found on agriculturally important hosts such as apple and pear, and in trap collections. Their morphological similarity makes identification difficult. Examination of specimens of both species fom a wide geographical range demonstrated that available keys, especially those based on European material, were not always accurate for North American specimens. Data taken from North American specimens is presented and a key is provided to aid in the identification of trapped alatae preserved in alcohol as well as slide mounted alatae and apterae of these two species.
Halbert, Susan E. and Voegtlin, David J.
"Morphological Differentiation Between Aphis Spiraecola and Aphis Pomi (Homoptera: Aphididae),"
The Great Lakes Entomologist, vol 25
Available at: https://scholar.valpo.edu/tgle/vol25/iss1/1