What are these white spots on the leaves of my oak tree?

Asked September 14, 2015, 6:01 PM EDT

A have some fairly new young trees that have leafed out this summer and they have what looks like little white round spots on them that look like there might be a bug or worm inside. The trees are kind of a burr oak. Can you please tell me what these are and how to get rid of them as I don't want to lose the trees? They are all over all of the leaves.

Denver County Colorado trees and shrubs gall wasp

1 Response

Without seeing a photo it's hard to say for certain, but if the white spots are woolly masses along the underside of the leaf, they are most likely from gall wasps. These are very common and don't typically present a major risk to the tree.

Gall wasps
are the single largest group of gall-making Insects. Gall wasps produce a wide range of galls from woody, rounded galls on stems or leaves to woolly or mossy galls. Essentially all insect galls found on oak or roses are produced by gall wasps.

Here is a link to our fact sheet with more information and treatment options if you so choose. Although, typically no treatment is recommended.

http://www.ext.colostate.edu/pubs/insect/05557.html

Good luck!