The elm flea weevil: A new pest found in Michigan

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.     

Dr. Jim Zablotny, the USDA/APHIS/PPQ Insect Identifier at the Detroit Metro Airport, identified a new state record for Michigan: the elm flea weevil, Orchestes alni (Coleoptera: Curculionidae). This pest has been in the Midwest since 2003 where it has been found in Ohio and Wisconsin. In Michigan, it has been found in Wayne, Monroe and Washtenaw counties. The European elm leaf beetle feeds extensively on elm leaves; it loves Siberian elms.

According to Ohio State University Extension entomologist Curtis Young, the European elm flea weevil, is commonly found throughout Europe. It was first identified in the northeastern United States in 1982. The tiny adult is black or dark brown, or brown with black spots on the back. It has a prominent beak and like other flea weevils, the hind femurs are enlarged to equip the weevil for jumping. Adults appear in the spring just in time to feed on the underside of newly developing leaves of Siberian elm. They soon begin to lay eggs along the leaf veins. The larvae feed as leaf miners for several weeks before they pupate. Adults emerge throughout the summer and resume feeding on the host elms until they seek overwintering sites on or near the host plants. There is probably only one generation per season.

A dorsal view of the Elm flea weevil.
Photo credit: Jim Zablotny, USDA/APHIS/PPQ

A side view of the Elm flea weevil.
Photo credit: Jim Zablotny, USDA/APHIS/PPQ

We would be very interested in knowing where else in Michigan this beetle occurs. If you come across a Siberian elm that is showing leaf feeding or leaf mining, look very closely for these tiny beetles on the underside of the leaves. If you find anything that comes close to the photographs shown here, please send some to:

MSU Diagnostic Services
101 Center for Integrated Plant Systems
Michigan State University
East Lansing MI 48824-1311
Tel 517-355-4536

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