P&PDL Picture of the Week for
July 10, 2006

Velvet erineum gall mite

Gail Ruhl and Karen Rane, Plant Disease Diagnosticians, Department of Botany & Plant Pathology, Purdue University

You may have noticed the appearance of red patches on leaves of silver maple trees. At first glance, the symptoms look like some sort of fungal growth on the undersides of the leaves, but this is not an infectious disease problem. The velvety patches are actually caused by a microscopic mite called the velvet erineum gall mite. The female mites stimulate leaf cells to develop abnormally into raised, felt-like areas in which they reproduce. Like most insect galls, these velvet erineum galls have virtually no impact on the health of affected maples, and control is not warranted.

Photos courtesy of Scott Gabbard, Shelby Co Extension Educator

Click image to enlarge

Living velvet on maple

Velvet erineium gall mite on maple

Living velvet on maple 10X magnification

10x magnification

Living velvet on maple 30X magnification

30x magnification

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service