Box Elder Bug vs Elm Seed Bug: Which Pest is the Best?

You may be familiar with the sight of boxelder bugs clustered in large groups on the sides of trees, buildings and sometimes your home. Did you know, though, that since around 2014, residents of Utah and Salt Lake County in particular have had a new bug on the scene? Introducing: the Elm Seed Bug

What’s the difference between a box elder bug and an elm seed bug?

At first glance, these two little pests might look a lot alike and they do belong to the same “true bug” or Hemiptera order. There are differences, though, that you might be able to spot:

  • The elm seed bug has a rust-colored rectangle on its back with a black triangle (called a scutellum) inside it. Boxelder bugs have orange or red outlines on their bodies.
  • The underside of an elm seed bug’s abdomen is red.
  • Boxelder bugs are larger, growing up to half an inch whereas elm seed bugs will only reach about a third of an inch in length.
  • Elm seed bug nymphs start appearing earlier in the year, around late May. You generally won’t see boxelder bugs until later in the summer.
  • Like their names suggest, boxelder bugs are found mainly on box elder trees but also on maple and ash trees. Elm seed bugs are found on elm, oak and linden trees.

What are the similarities between elm seed bugs and box elder bugs?

Both types of bug also have plenty in common:

  • They are related to stink bugs so they will let off a bad smell if crushed.
  • Both bugs will cluster on trees and buildings and will try to enter buildings for warm places to spend the winter.
  • Neither bug is dangerous to humans.

How do I prevent these bugs from infesting my home?

You can use the same approach to get rid of both the boxelder bug and the elm seed bug. If they’ve already found their way in, you may not even realize until they start reappearing again when the weather begins to warm up. To prevent the bugs from infesting your home, you can try these tips:

  • Use a sealant or caulk to seal up any gaps around thresholds or windows on the exterior of your property.
  • To stop the small elm seed bug from entering under your door, add a door sweep or tightfitting threshold.
  • Ensure all door and window screens are in good shape.
  • Vacuum up bugs if they have entered your home. A good tip is to put something like a nylon stocking over the vacuum hose and secure it with an elastic band. The bugs can then be tied up in the bag and disposed of with them actually going into your vacuum cleaner.
  • Think about getting rid of elm or boxelder trees that are on your property if you have large numbers of bugs on them.
  • Schedule a pest control company to apply barrier treatments around your home.

As average temperatures increase, you’re likely to see these bugs around for longer periods of time but if you use some of the tips above, hopefully you’ll be able to keep them outside where they belong.