Friday, December 6, 2019

An Uninvited Winter Guest


Have you been getting this visitor in your home of late?

Conifer Seed Bug
Image from bugguide.net Creative Commons copyright 2019 Davad Thornberg 

Conifer seed bugs (Leptoglossus occidentalis) seek shelter over the winter and often end up in homes. They are classified as nuisance invaders because they don’t harm humans or our homes.

During the growing season Conifer seed bugs feed on seeds, primarily of conifers. They have distinctive enlargements on their hind legs which places them in the leaf-footed bug family (Coreidae). These bugs can give off an odd odor, reminiscent of Pine-Sol cleaner.

During the winter, adults are semi-dormant and live off fat reserves. In the spring Conifer seed bugs return to the outside and feed on plants. In late spring, females will lay eggs, and once they hatch, the immature insects feed on seeds.

Insecticides are not recommended for use on Conifer seed bugs. The most effective treatment is to keep the house well-sealed in the fall when these insects are looking for shelter. Individual bugs can be vacuumed.


For more detailed information please see Conifer Seed Bugs CSU FactSheet 5.588


For a list of common nuisance invaders organized by month see Dr. Whitney Cranshaw’s Checklist of Common Insect Related Events - Colorado High Country Areas




By Kristina Hughes, Clear Creek County Master Gardener