Potato aphid (Macrosiphum euphorbiae) and others
Pest description and damage Clusters of slate gray aphids can congregate in prodigious numbers along stems and under flowers of Euphorbia. Aphids tend to be small (0.0625 to 0.125 inch in length), oval to pear-shaped, soft-bodied insects with piercing-sucking mouthparts. Aphids may vary in color depending on species from greenish to dark grey.
For biology, life history, monitoring and management
See "Aphid" in:
See Table 1 in: