ash bead gall mite

not listed

not listed

not listed

Ash bead gall mite occurs in eastern North America from New Brunswick to Minnesota south to Alabama and Nebraska. It is uncommon in the Midwest based on the number of reported sightings, but it is probably underreported.

Ash bead gall mite is robust, spindle-shaped, yellowish, and just 1⁄100″ (210 to 260 microns) in length. It is large enough to be seen by the naked eye without magnification. The identifying features are the shape of the claws, the texture on the back plate (dorsal shield), the presence or absence of microscopic bumps on the second body segment, and the flap covering the female genitalia. None of these features can be seen without a microscope. However, identification in the field is easily made by noting host species and the properties of the abnormal growths (galls) it produces.

The galls appear on the leaves of green ash and white ash. When present, there are usually several galls scattered randomly on the lateral veins of a single leaflet. Each gall is a small, kidney-shaped, greenish-yellow capsule.

Total length: 1⁄100″ (210 to 260 microns)

Green ash and white ash

The life cycle apparently requires alternation of generations. Adults emerge on the underside of the leaf in late summer.

Sources

7, 29, 30.

Uncommon