Asked July 02, 2015, 1:27 PM EDT
Boulder County Colorado
It appears you have currant aphids. Click on this link for more information: Aphids on Shade Trees and Ornamentals.
During the dormant season applications of oils should effectively kill overwintering eggs -- this you can do in the early spring. Contact aphicides, as well as systemic insecticides, can provide control, although insecticide options are very limited on edible fruit-bearing plants It would be helpful to cut off the affected areas and bag them for trash.