Gall-Making Aphids (IMAGE) Howard Hughes Medical Institute Caption Hormaphis cornu aphids feed on witch hazel leaves and coax the plants into making galls. Credit David Stern Usage Restrictions Must use credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.