Eastern Box Elder Bug (Leptocoris trivittatus) is a native insect common in the eastern parts of Canada and United States that is mostly considered a common household pest.   Because this insect does not harm the health of trees, it is not considered a Forest Health Concern; Therefore the City of Toronto does not treat for Eastern box elder bug.  Management options for this insect can be found below.

Life Cycle and Description
In the spring, the overwintering insects lay eggs on stones, leaves, grasses, shrubs, etc. The hatched nymphs (Fig.1) are red in colour. In the summer they start to feed on fallen Manitoba maple seeds. The next stage of their life cycle, the adult bugs are more dark/black in colour with more distinct orange markings (Fig. 2) and continue to feed on the fallen seeds of the female Manitoba maple well into the fall.

These insects are more active during the day throughout the spring and summer months and tend to hide in the evenings and overnight.  As fall approaches, they tend to congregate, sometimes in potentially large numbers, on sunny facing sides of buildings, trees, stone walls, etc. as they warm themselves in the sun (Fig.3).  As evenings approach, they once again seek shelter.  This is also the time of year that they tend to begin finding their way into homes and inside structures as they attempt to find places to hibernate and overwinter. Box elder bugs are mostly an annoyance to home owners because of this behaviour.

Eastern Box Elder Bug - nymphs Adult Eastern Box Elder Bug

Adult Eastern Box Elder Bug

Hosts and Behaviour
Box elder bugs feed primarily on the fallen seeds of the Manitoba Maple trees (Acer negundo) (Fig. 4).  These insects are harmless to humans and do will not damage any plant material or trees.
Box elder bugs are often a nuisance to home owners around their homes and other structures around their property where Manitoba maple trees are present.

Manitoba Maple with seeds

Specific Management Practices for Control of Eastern Box elder Bug
Because this insect does not harm the health of trees, it is not considered a Forest Health Concern; Therefore the City of Toronto does not treat for Eastern box elder bug.  We do recommend the following to individuals that are experiencing issues with this insect:

  • It is not recommended to squish these insects as they can omit a foul odour when crushed. This odour has potential to draw further insects to the area, in turn exacerbating the situation
  • Focus should be on preventing the insects from accessing homes and buildings.The best way to keep box elder bugs out of building is to make sure that there are no entry points. Filling gaps around windows and doors, repairing or filling holes in foundations and using window and door screens will help to prevent their entry.
  • The use of an insecticide labelled for box elder bug control could be applied, by treating the exterior of the building at the time of the swarming in the fall. Treat sidings, windows, doors and the foundation the building with an insecticide. Many pest control companies provide box elder bug control around homes.
  • An alternative to synthetic insecticides is a mixture of soapy water that can be used to spray the insects directly has shown to have some knock-down effect
    • Recipe
      -2 tbsp. of liquid dish soap
      -1 litre of water
      -2 tbsp. of cooking oil (IE. canola, olive)
    • Instructions
      -Mix ingredients together and put into empty spray bottle or hand pump sprayer.  Spray insects directly ensuring to cover them as best as possible with the solution to achieve best results.  Spray as often as necessary.  Soap only kills the bugs that are being sprayed and has no residual effects once it is dry.

    The Ontario's Cosmetic Pesticides Ban Act prohibits pesticides to be used for cosmetic purposes on lawns, vegetable and ornamental gardens, patios, driveways, cemeteries, and in parks and school yards. There are no exceptions for pest infestations (insects, fungi or weeds) in these areas, as lower risk pesticides, bio-pesticides and alternatives to pesticides exist. Over 95 pesticide ingredients are banned for cosmetic uses.

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