Western Conifer Seed Bug (Stink Bug)

This three-quarter inch brown colored bug has the habit of entering buildings in the late summer or early fall as it seeks a protected site to spend the winter. These bugs do not bite or sting, and they cause no damage to the home. They do not reproduce in the home nor do they feed once inside your home. They live off fat reserves and during the cool season they are semidormant. They will give off a pungent order if you handle them and they also make a buzzing sound when flying. This unwanted houseguest is the western conifer seed bug or Leptoglossus occidentalis.

In the early 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 lay rows of eggs on needles, which hatch in about ten days. Yound nymphs begin to feed on green cones and needles of pine and Douglas fir and pass through five stages until they reach adulthood by late August. The nymphs are orange and brown, becoming reddish brown as they develop. Adults feed on ripening conifer seeds until they seek their winter quarters. There is only one generation per year.

These insects are very difficult to completely exclude from the home. The best action is to attempt to seal cracks, doors and windows. Screening attic or wall vents, chimneys and fireplaces may help to mechanically block their points of entry. However, the best efforts seem to be unsuccessful in preventing these bugs from finding a way inside. Vacuuming or otherwise disposing of individual insects is the best means of controlling these accidental invaders. There are no pesticides specifically registered for control of this or for indoor use.