in the spring and early summer, both aphid species infest young trees, water sprouts, and vigorous terminals on apple, pear, and quince. Unlike rosy apple aphids, which spend part of their life cycle on plantain, both green apple aphid and spirea aphid remain on apple year-round.
Aphid nymphs and adults suck sap from apple leaves, favoring rapidly growing terminal and water sprout foliage. Leaf curling indicates aphid presence, but causes little or no damage. Aphids excrete large amounts of honeydew which may collect on fruit and foliage. Black sooty-mold fungus can develop on honeydew, discoloring fruit.