White spots on my maple trees

Asked February 17, 2020, 2:44 PM EST

This winter I noticed white sports on the bark of my Maple Trees. Three different kinds of Maple Trees. I had read it could be a kind of wasp that can eventually kill the trees. Please help

Scott County Minnesota

1 Response

This appears to be White spot lichen phylctis argena which is usually not harming your tree. This tends to grow on older trees and shrubs.
http://www.florafinder.com/Species/Phlyctis_argena.php
To my eye, this tree looks like it may need some pruning (not for the white spots but because of the dense systems of branches.
A certified arborist could advise you on pruning and the spots. https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional
Thank you for writing.