welcome to the

     Douglas county conservation district

serving landowners in Douglas County, Colorado for over 50 years

                                Box 688, 7519 E. Hwy 86, Franktown, CO 80116, 303-688-3042 ext. 100

Hackberry Nipple Gall

About Hackberry Nipple Gall

Lives on hackberry.  Adult psyllids are about 4 to 5 mm long, and look like miniature cicadas.  The tiny, yellowish nymphs rapidly become enveloped by gall tissue and are rarely seen.  Nipple galls are light green, nipple-shaped, and about 4 mm in diameter. 

Psyllids overwinter as adults in bark cracks and crevices.  After mating in spring, females lay eggs on new growth.  Nymphs feed on new growth all summer, causing galls to form on the underside of leaves.  In September, large numbers of adults emerge from galls and collect around doors and windows.

Insect injury occasionally causes premature leaf drop, but trees are not seriously damaged.

To Control

Control is not generally needed.  Leaves can be sprayed with carbaryl in spring when leaves are expanding.  Raking and burning infested dead leaves kills beneficial wasps that parasitize the psyllids and overwinter inside the galls.