Hackberry “Pimples”
- Jun 30
- 1 min read
Q: My hackberry tree leaves have strange “pimples” on the underside of many of the leaves. Is this a problem?
A: This is called a Nipple Gall. Those tiny, nipple-like bumps covering hackberry leaves are caused by the hackberry nipple gall psyllid, a tiny insect that lays its eggs on newly emerging leaves in spring. As the young insects feed, the leaf tissue grows around them, forming the distinctive galls. While they may look alarming, they rarely harm the tree.
Control: Control is usually not necessary. Nipple galls are primarily a cosmetic issue and do not threaten the health of established hackberry trees. Insecticides are generally ineffective because the insects are protected inside the galls, and by the time the galls are visible, it's too late to treat. The best approach is simply to let nature take its course.
Read our Q & As with Keith Funk answering common Colorado gardening questions here. See his website: gardenwiseguy.com and hear him on the Garden Wise Radio Show
