Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001737
11/12/99
Elm Leaf Beetle
As its name implies, the elm leaf beetle (Vis. 1) is a
problem on elm trees. It is most common on Chinese or
Siberian elm and can also be a problem on zelkova.
The adult beetles are yellowish-green with black stripes
in the middle and on the sides of the wing covers. There
are also two black but indistinct black spots at the base
or front of the wing covers. The larvae (Vis. 2) are short,
stubby caterpillars that can appear as black with yellow
markings or yellow with black markings.
The larvae cause most of the damage. They skeletonize the
leaves which then turn brown. Repeated, severe
infestations may kill a tree or weaken it so it may
succumb to some other problem.
The adult overwinters in homes or other protected areas.
Those adults overwinter in homes can be a nuisance
particularly when they begin to look for overwintering
sites. The adults emerge in the spring and the females
lay eggs on the leaves. The larvae hatch out and begin
feeding. Mature larvae will move to the lower part of the
trunk and pupate. The pupal cases are yellow and can be
seen on the trunk. The adults emerge in one or two weeks
and lay eggs for the second generation. It is the second
generation adults that overwinter in homes. The larvae
cause most of the damage in June and again in August.
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to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
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a commercial product or company.
This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
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