The western conifer seed bug has become a nuisance pest in many Rhode Island homes. The bug has the habit of entering buildings at the onset of cold weather in the late summer or early fall as it seeks 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.

History:

The range of the western conifer seed bug has been expanding. Confined to the Western coast of the United States until the 1960s, this insect began to move east rapidly in recent decades. By 1990 the insect had reached western New York, and by 1996 had arrived in Rhode Island.

Description:

The western conifer seed bug belongs to the family Coreidae, commonly called leaf-footed bugs, and like many members of this family, it has a flattened, leaf-like expansion on the hind legs. The adult is about 3/4 inch (16-20 mm) 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. The leaf-footed bugs use piercing-sucking mouthparts to pierce the scales of conifer seeds and suck out the seed pulp. The list of host plants includes white pine, red pine, Scots pine, Austrian pine, mugo pine, white spruce, Douglas fir and hemlock. When these trees are grown near homes, the bugs may seek the nearby buildings as an overwintering site.

Life Cycle:

In spring these bugs move outdoors to nearby coniferous trees. The bugs feed on the developing seeds and early flowers of different species of conifers. Females are reported to lay rows of eggs on needles of the host trees, which hatch in about 10 days. Young nymphs then begin to feed on tender cone scales and sometimes the needles. The nymphs are orange and brown, becoming reddish-brown to brown as they develop. Nymphs pass through five stages and reach adulthood by late August. Adults feed on ripening seed until they seek overwintering quarters.

Control:

If these bugs are a problem in your area, you may screen attic or wall vents, chimneys and fireplaces to mechanically block their points of entry. Eliminate or caulk gaps around door and window frames and tighten up loose fitting screens, windows or doors. There are no pesticides specifically registered for control of the western conifer seed bug either indoors or out. Use a vacuum to remove these insects from the home.

Adapted from the Cornell Cooperative Extension and the URI Department of Plant Sciences, 1999