Witch hazel gall aphid on river birch. This aphid occurs later in the spring. Photo by: B. A. Kunkel, Ornamentals IPM Extension Specialist, University of Delaware

Witch hazel gall aphid on river birch. Photo by: B. A. Kunkel, Ornamentals IPM Extension Specialist, University of Delaware

Woolly beech aphids are active later in the spring. Photo provided by: B. A. Kunkel, Ornamentals IPM Extension Specialist, University of Delaware

Winged adult green peach aphid. Photo provided by: Scott Bauer, USDA Agricultural Research Service, Bugwood.org

Green peach aphid adult giving live birth. Photo provided by: Jim Baker, North Carolina State University, Bugwood.org

Green peach aphids (adults, winged adults, immatures). Photo provided by: Whitney Cranshaw, Colorado State University, Bugwood.org