Knowledgebase
Weird egg like things under hundreds of leaves in my yard. #777529
Asked November 10, 2021, 10:03 AM EST
I have hundreds of these small round 'things' on the bottoms of several tree leaves. They are white and very hard. I am afraid to use the leaves for mulch. Are they eggs? If so, what is lurking within them and will they explode into my gardens? Susan
Denver County Colorado
Expert Response
Susan,
Those are galls (ie. abnormal growths) that get created when hackberry psyllids lay eggs on the foliage in the spring and the young developing nymphs feed on the leaf tissue. The galls are left after the insects have flown.
The insects are very common on hackberry trees but they won't spread to other plants or explode in your garden. The galls themselves are an aesthetic nuisance but - silver lining! - in the spring, birds are attracted to the trees to feed on the insects (and squirrels, too, unfortunately).
Here is an article with lots more information about Hackberry Nipple Gall that was written by the CO Extension Horticulture Agent in Larimer County:
http://csuhort.blogspot.com/2017/08/hackberry-nipple-gall-name-alone.html
