The most common pest aphid on legumes like alfalfa in northwestern N. America. It causes hundreds of millions of dollars of crop damage a year.
Non-native, first reported in 1877, from the Palearctic region.
Foottit, R. G. et al.: Adventive Aphids (Hemiptera: Aphididae) of America North of Mexico. Proc. Entomol. Soc. Wash. 108 (3), 2006, pp 583-610.