Elm Leaf Beetle
Attribution: Georg Slickers, [GFDL or CC-BY-SA-3.0]
About 1/4-inch in length.
Medium green with a dark stripe on each wing cover.
Elm leaf beetles infest elm trees where the larvae feed upon the trees leaves. The larvae eat between the leaf veins, leaving the leaf with a "skeletonized" appearance. During late summer, the larvae fall off the tree into the leaf litter underneath to pupate. The adults emerge and search for a place to overwinter. They are attracted to the warmth emitted by nearby buildings and will crawl into cracks and holes in the buildings' exterior walls. They crawl as far back as they can into wall voids and attics. During warm winter days, some beetles may make their way into the interior of the building. Beetles, therefore, may be seen throughout the winter and spring.
Outdoors, elm leaf beetles are associated with elm trees. During the fall, they may enter buildings through exterior cracks and holes looking for a protected place to overwinter. Usually, the south and west walls of a building are affected as the fall sun warms these walls.
The best way to control elm leaf beetles is by prevention as described below. If the beetles are already inside, it takes a professional to find and treat the right areas to minimize the numbers of beetles seen inside. If your home has experienced a problem with elm leaf beetles, take the following steps next summer to prevent a recurrence:
- Seal as many cracks and holes on the outside of the home as possible, especially on the south and west walls where the sun heats the home during the late summer and fall.
- Be sure that all foundation and attic vents have tight-fitting screens. Check both the soffit vents and any gable vents or turbine vents on the roof.
- Have your Terminix professional treat the outside west and south walls of the home near the eaves. This treatment should be completed in mid- to late August.