Hackberry nipple galls are caused by?

• A. Psylids or jumping plant lice
• B. Aphids
• C. Scale insects
• D. Cicadas

Answer: (A)

Hackberry nipple galls form as a reaction to feeding and egg-laying by a tiny sap-sucking insect called a psyllid, or jumping plant lice. On hackberry leaves, these nymphs stimulate the leaf tissue to swell into small, nipple-like protrusions, which is why they’re called nipple galls. The galls are mostly cosmetic and don’t usually harm the tree. Aphids, scale insects, and cicadas interact with hackberry in different ways and don’t produce these characteristic nipple-shaped growths, which is why psyllids are the correct cause.