Maple Bladder Galls—“Freckles” on the Leaves
By Kathleen Cue, Nebraska Extension Horticulture Educator
If you have a sliver or red maple tree, you’ve most likely noticed small raised bumps on the leaves. Tree owners will call them “freckles”, “measles” and sometimes even “zits”. Whatever they are called, maple bladder galls are caused by a very tiny mite. The galls themselves are made up of plant tissue and are a part of the leaf. Maple bladder gall mites live, eat and mate inside the galls and are well-protected from any application of a miticide.