Friday, November 20, 2009

Abundance of Hackberry Gall Nipple Makers

Many residents that live in neighborhoods with hackberry trees have been noticing many small cicada looking insects, about 3/16 inches in length with spotted wings on their window screens and doors. These insects are adult hackberry gall psyllids or also called hackberry nipple gall makers. In the fall, these insects invade indoors looking for an overwintering site. Normally, they will overwinter under the bark of trees, but will also come indoors through any cracks and crevices such as around windows and doors usually at night since they are attracted to indoor lights. However, those that come inside are going to die.
In the spring, the adult psyillds will emerge and lay eggs in the leaves of hackberry trees. When the egg hatches, the developing psyilld begins feeding and the leaf begins to form a small pocket around the psyilld as the insect develops, forming a gall. The galls that are produced vary in size from 1/8 to ¼ inch and are found on the leaves and petioles. The adult gall will then emerge in the fall. Even though the galls can be unsightly on the leaves and sometimes cause premature leaf drop, they do not appear to affect tree health. This means no chemical treatments are recommended.
Hackberry psyllids are not harmful to people or pets and will not attack indoor plants or furnishings. Since they are a seasonal annoyance, residents can vacuum them to remove them as needed. As the temperatures fall, so will the hackberry gall psyilld population!

Photo of hackberry gall psyllids, Pachypsylla sp. (Homoptera: Psyllidae), adults. Photo by C.L. Cole, Texas A&M University.

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