Pine Seed Bugs

Pine seed bugs are related to assassin bugs but are quite different in appearance and habits.

These are insects that have been showing up in homes for more than 10 years. They are often misidentified as assassin bugs or stink bugs. They are in the leaf footed bug family and are called western conifer seed bugs. They are native to western North America and have gradually migrated eastward. The first records in the U of Guelph collections are of specimens taken in homes in the fall of 1985.

Pine seed bugs are related to assassin bugs but are quite different in appearance and habits. They are fairly large, from 10 to 40 mm in length. They are a dull brownish colour with an orange back under their wings. They have long legs and tend to be sluggish. They often gather at windows inside homes.

They differ from assassin bugs in that they are plant feeders, feeding on conifer trees including various types of pine, white spruce, Douglas fir and hemlock. Adults feed on ripening seeds where they pierce the scales of conifer seeds and suck out the pulp. Nymphs feed on tender cone scales and sometimes needles. Damage to trees is not usually a problem but severe infestations have caused damage to trees in the west. Homes surrounded by stands of conifer trees tend to have a greater problem with pine seed bugs.

These insects do not cause damage to homes or pose a threat to people or pets. They are strictly a nuisance. In the fall, hey will congregate on the sunny sides of homes and enter in through any gaps that they find. They go dormant over the winter but often become active inside on sunny days. Pine seed bugs give off a strong odour when crushed and make a buzzing sound when they fly. Because they have a sharp beak for piercing cones and seeds, they can give a painful nip if mishandled.

Control involves sealing any cracks or openings on the exterior. Inside, use a vacuum or broom to sweep them up. Wear gloves if you handle them. Seasonal exterior treatments for pests such as cluster flies or paper wasps will also help prevent pine seed bug infestations.