Problem: Rose aphid
Macrosiphum rosae Rose aphids do little damage in small numbers. Plants can tolerate fairly high populations without much effect. The aphids are extremely prolific, however, and populations can rapidly build up to damaging numbers during the growing season. Damage occurs when the aphid sucks the juices from the rose stems and buds. The aphid is unable to digest fully all the sugar in the plant sap and excretes the excess in a fluid called honeydew, which often drops onto the leaves below. A sooty mold fungus may develop on the honeydew, causing the rose plants to appear black and dirty. Ants feed on the sticky substance and are often present where there is an aphid infestation. When aphid populations are high, flower quality and quantity are reduced.
Apply an insecticide labeled for this pest, following label directions.