Inspecting a Western Conifer Seed Bug Infestation

The western conifer seed bug is a type of Heteroptera or true bug. Western conifer seed bugs plague a big part of the continent of North America. With an appearance that looks like a strange hybrid between a locust and a beetle, western conifer seed bugs are often dark or reddish-brown in colour. Conifer seed bug (leptoglossus occidentalis) is often mistaken as boxelder bugs, kissing bugs, or other similar looking bugs.

They have a length of 16 to 22 millimetres, depending on gender. Once disturbed, they take off and fly. These bugs can also be found resting on different plants where they try to consume the milk or sap produced by the plants.

These bugs are native to the United States’ west coast region. But since the 1990s, they have also settled on the east coast. Western conifer seed bugs are only regarded as minor pests of coniferous trees they attack. But, they can become a major inconvenience the moment they get inside your home.

You can handle small infestations through sealing up cracks and gaps that can serve as entry points for these bugs. These include chimneys, holes in screens, loose window fittings and others.

You can also capture escapees using a vacuum or you can pick them up by hand. However, a licensed pest control specialist should be consulted for larger infestations.

Once found in large numbers, western conifer seed bugs can damage and even potentially kill off trees, specifically developing and younger trees. Homeowners who have trees and yards should watch out for any potential problem.

During fall and winter when the weather is cooler, they usually try to move indoors as they seek shelter. In regions with large forested areas, they usually invade homes in big groups, resulting in a large and unsettling infestation.

Signs of Infestations of Western Conifer Seed Bugs

Since these insects have limited activities during winter, the perfect time to detect an infestation of western conifer seed bugs is early fall and late summer. This is the time when these pests move indoors to flee from the imminent onset of the cold season.

Gaps and cracks in frames of windows and doors make entering your home easier for these true bugs. Residents who want to check for infestations must monitor openings such as fireplaces, vents, and chimneys.

In the event of rather severe infestations, large populations of western conifer seed bugs might become disturbed or agitated and give off a unique odour often described as citrusy and acrid.

Why Do You Have a Problem with Western Conifer Seed Bugs?

Are there plants around and inside your property? Western conifer seed bugs love plants with sap or milk. There is a higher chance that you will have these bugs as visitors when you have juicier plants.

These bugs are not really travelling in packs on purpose yet they migrate in mass to sources of food. If you are having problems with western conifer seed bugs, it is likely because they are interested in a food source in your property. Always check conifer trees or plants around and on your property to keep these bugs away.

Where Can You Find Western Conifer Seed Bugs?

As you have probably guessed by now, western conifer seed bugs have earned their name because you can commonly see them feeding on saps housed within the developing cones of conifer plants. While you can also find these pests on full-grown plants, seeds are their main target due to the abundant amount of sap in them. When it is time for them to reproduce, these bugs look for an appropriate host plant. 


In general, the most effective way to prevent the infestation of western conifer seed bugs is by getting rid of all potential entry points.

  • Homeowners must check the proper fit of windows and doors and replace or tighten those that are too loose.
  • Seal off wall cracks and door and window frames to get rid of access points of these invading insects.
  • You might also want to install finely woven screens over your vents and chimneys.
Again, when the infestation is too hard to handle yourself, employ pest management services who are knowledgeable on how to deal with a large number of seed bugs as well as other species of pests that often spend winter season inside homes and buildings.