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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Imported Longhorn Weevil

This article was published originally on 7/14/1995
The Insect Whose Name is Longer than it is!

The imported longhorned weevil, like its close relative the strawberry root weevil, is a common "accidental invader" that crawls into houses and buildings from outdoors by mistake. The weevils are harmless; they do not damage the house or furnishings and they can not bite or sting people or pets. They are merely a nuisance by their presence. Outdoors, however, the ILHW is often responsible for varying amounts of defoliation on landscape and garden plants. Foliage may appear "notched" at the edges because of feeding by the adults, or flower buds may be fed upon and damaged.

Imported longhorned weevils are approximately 1/4 inch long and are shaped like a pear or a light bulb. The color is mottled tannish-gray (on living insects; preserved specimens appear black). The weevils have six legs and a long pair of antennae that can give rise to a vague similarity to a tick. Legs and antennae seem rather long for the size of the insects, and the antennae have an "elbow" or bend in the middle.

The larvae of these weevils are grubs that live in the soil and feed on the small roots of many different plants, including aster, clover and turfgrass. They do not cause apparent damage to the plants and control of the larvae in the soil is not practical nor necessary.

Some of the invasion by longhorned weevils can be prevented by exclusion techniques that close their routes of entry. Look for and seal cracks and gaps through which the adults can crawl into the building. Spraying malathion, Dursban or diazinon insecticide on and along the foundation and in outdoor areas of weevil abundance may be of some benefit. Adults already inside need only be vacuumed or swept up and discarded. Household aerosol insecticides are not very effective for controlling these weevils.

Control of adult weevils in the garden may be difficult. Often, small amounts of leaf feeding can be tolerated rather than resorting to insecticide cover sprays of Sevin, rotenone or malathion.



This article originally appeared in the July 14, 1995 issue, p. 105.

Year of Publication: 
1995
Issue: 
IC-470(18) -- July 14, 1995