Western Conifer Seed Bug—Leptoglossus occidentalis

The western conifer seed bug has become a nuisance pest in many homes. The bugs enter buildings at the onset of cold weather in the late summer or early fall seeking a protected site to spend the winter. These bugs do not bite or sting, nor do they cause damage to the home. They will, however, give off a pungent odor if you handle them. They also may make a buzzing sound when flying.

western conifer seed bug
western conifer seed bug
western conifer seed bug

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The adult western conifer seed bug is about 3/4 inch in length and is a dull brownish color. There is a faint white zigzag stripe across the midpoint of its upper surface. When the insect takes flight, it lifts the wings to reveal bright yellowish-orange areas on its back. It has long antenna, usually as long as its body. It has thick, flattened tibia on its hind legs. These insects are often mistaken for stink bugs as they produce an unpleasant odor when alarmed.

Control Information

In many instances, organisms that we deem "pests" may not be pests, and other organisms may only be pests in certain instances and control may not always be warrented. Usually, western conifer seed bugs are not considered serious pests and may occasionally be indoors in the winter months. Recently, they have been found in Europe and are considered to be serious pests of conifers there.


Dig Deeper - Scientific Studies

  • Biology, Ecology, and Management of Hemipteran Pests in Almond Orchards in the United States

    Summary: Seveal hemipertan insect pests exist in almond orchards and include lace bugs, plant bugs, stink bugs, and leaffooted bugs. Pests in the hemipteran order use needle-like mouthparts to pierce the surface of plants and fruits, which can cause considerable damage and plant deformities. This paper delves into the biology, ecology, and management practices of these hemipteran pests in almond orchards to summarize the current research available on these pests.

More Information

[Photos, left to right: Whitney Cranshaw, Colorado State University, Bugwood.org; Joseph Berger, Bugwood.org; David Cappaert, Michigan State University, Bugwood.org]