Green pine aphids feed on the underside of pine needles growing at the crown of the tree (Chilima 1991). Infestations cause the needles to turn yellow and under high infestations the growth of the tree is stunted. Infestations on stressed trees can lead to top die-back or even tree death in extreme cases. Sooty mould can grow on the honey dew excreted by the aphids feeding on the sap and this can give the needles a look of being covered in black precipitate (Murphy et al. 1991).

The pine needle aphid exhibits cyclic reproduction. This consists of altering sexual and asexual generations. The egg stage has an overwintering period. The eggs hatch in the summer and produce stem mothers which reproduce parthenogenetically and vivarously (bringing forth live young). The subsequent generations are known as the viviparae. These generations consist of apterous (wingless) and alate (winged) females. In the summer they reproduce parthenogenetically. The sexual stage usually appears at the end of summer and consists of a true apterous female and males that can be apterous or alate. This final generation of females is oviparous and lays eggs, which remain dormant until the following spring (Palmer 1952).

Studies conducted in Africa (introduced) indicate the species has a reduced life cycle and may reproduce throughout the years without a sexual generation. All life stages feed on the underside of pine needles (Murphy et al. 1991)

The braconid parasitoid, Diaeretus leucopterus, has been considered as a potential biological control agent for Eulachnus sp. (Murphy & Völkl 1996) together with Entomopthora planchoniana Cornu, an entomogenous fungus (Katerere 1983).