Winter House Guests

Western conifer seed bug, left (credit NY State IPM Program at Cornell University), commonly mistaken for the brown marmorated stink bug, right (credit Oregon State University).
Photos: Western conifer seed bug, left (credit NY State IPM Program at Cornell University), commonly mistaken for the brown marmorated stink bug, right (credit Oregon State University).

(By Laura Ray, Communications Coordinator)

A couple years ago, my family went away for a few days during winter break for a lovely getaway in the Oregon woods. We returned home to Eugene, well rested and relaxed, and found an unexpected house guest: a rat had taken up residence! We figured that during the start of the heavy winter rains, it was seeking refuge and had somehow snuck into our home.


The rat tormented us for days. At night in bed, we could hear it scurrying around. During the day, I never knew where the rat might be lurking. Thankfully after a few days it was caught in one of the traps we set up around the house. We worked with our landlord to ensure that any crevices or openings into the house were sealed up, and we have been rat-free ever since. To prevent rats and mice from entering your home, it’s important to fill all openings with non-chewable materials such as steel wool or copper mesh. Read more on our website about dealing with rats and mice.

Seed Bugs- Not Stink Bugs!

Another unwanted winter house guest that is common in the Northwest is the seed bug. Seed bugs are often mistaken for stink bugs, as both smell when squashed.Both are slow-moving, brown bugs with long legs and antennae, up to about ¾ inch in total length.Several kinds of seed bugs are found in the Pacific Northwest, and a common native species is the western conifer seed bug, Leptoglossus occidentalis.Here is the easiest way to distinguish a western conifer seed bug from a stink bug: the seed bug’s lower hind leg is slightly widened on each side, while the stink bug has an even, cylindrical leg(see photos above).

Western conifer seed bugs often come indoors during winter to find warmth and they can be quite annoying, making a loud buzzing sound when flying.Otherwise, they are mostly harmless and they should eventually die in a building without moisture and conifer bark to keep them alive. If you use firewood, be sure to store it outdoors.You can try to prevent seed bugs from entering your home through small crevices by caulking and sealing all cracks. To clean up large numbers of seed bugs, use a shop vacuum with soapy water inside.


Ladybird beetles, aka “ladybugs,” are very helpful in the garden since they eat plenty of aphids, mites and other insects. But when ladybugs enter your home as the weather turns cold, they can turn into a nuisance. Gently remove them from inside your home and put them outside under some fallen leaves, so they can overwinter there. Try using a vacuum on the lowest setting, with a lightweight piece of fabric on the end, to collect the beetles and place them outside. Like with seed bugs and other small critters, the best way to prevent ladybugs from getting inside is by caulking all crevices around doors and windows, and repairing any damaged siding.

Natural Pest Repellants

There are a number of environmentally friendly repellants derived from natural ingredients that can help deter pests, including these home remedies. Many people swear by peppermint oil for keeping away spiders, mosquitoes, mice and other pests. There is some scientific evidence of peppermint oil’s effectiveness, but nothing very conclusive. Our recent Creepy Crawly Sweepstakes featured a natural insecticidal soap called Peppermint Fury. If you find other natural solutions to your household pest problems, we would love to hear about it!

For expert advice tailored to your pest or weed issues, check out our sliding scale Pest and Weed Management Consultation services.

  1. Voyle G. Western conifer seed bug or brown marmorated stink bug? [Internet]. East Lansing (MI): Michigan State University Extension; 2012 Feb 2 [cited 2020 Dec 15]. Available from:
  2. Bush MR, Collman S, Spichiger S. Emerging pests in Pacific Northwest ornamentals [Internet]. Oregon State University: Pacific Northwest Extension; updated 2020 Mar [2020 Dec 15]. Available from:
  3. Farnsworth E. They’re shacking up for the winter — in your house [Internet]. Amherst (MA): Hitchcock Center for the Environment at Hampshire College; 2012 Dec 8 [cited 2020 Dec 15]. Available from:
  4. Washington State University Extension. Seed bugs [Internet]. Puyallup (WA): Pestsense; 2015 Sept 3 [cited 2020 Dec 16]. Available from:
  5. Records E. Ask an expert: beatle mania! [Internet]. Oregon State University Cooperative Extension; 2018 Oct 3 [cited 2020 Dec 16]. Available from:
  6. Stark EM. Attract ladybird beetles (“ladybugs”) to your Northwest garden humanely [Internet]. Real Gardens Grow Natives; 2016 Jun 15 [cited 2020 Dec 16]. Available from:,please%20don't%20kill%20them. 

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  • Laura Ray
    published this page in BLOG 2020-12-18 10:44:44 -0800