Knowledgebase
Serviceberry Tree Problem #656168
Asked June 25, 2020, 7:27 PM EDT
Do you happen to know what these growths are on my serviceberry tree and, if they are harmful to the tree, how I can treat them? Thanks!
Livingston County Michigan
Expert Response
The bumps are called galls and are created by either a midge or a wasp that has laid its
eggs on the leaf. When hatched the tiny insects suck juices from the leaves. The leaves produce leaf tissue that covers the
developing larvae; hence the "bumps. The galls effectively shield the insects from insecticides.
Therefore, we do not recommend the application of insecticides.
If you look around, the leaves and stems of native trees and shrubs are frequently covered in galls of all sorts, sizes and colors, but they normally do not affect the health of the plant unless the number of galls is excessive. In your photos, I do see a fair amount of green leaf tissue so the plant should be able to sustain itself,
I
can't guaranty that your shrubs won't exhibit galls in the future.
However, your shrubs would be better able to take such an infestation if they are well-maintained and not competing for water and
nutrients with grasses and weeds and all their cultural needs are met.