Are you able to identify the bug that has infested my Linden tree and give advice on how to get rid of it if it is harmful to the tree or garden?
Thank you for contacting the Toronto Master Gardeners with this timely question.
The bug in question is European firebug (Pyrrhacoris apterus). There has recently been multiple sightings of this bug in the GTA. According to the City of Toronto’s Fact Sheet on Firebug “Red fire bugs feed on the fallen seeds from a wide range of plants. The most common host plant that the insects are found on in the G.T.A. are linden trees (Tilia sp.).”
As day light shortens these bugs are looking for places to overwinter, generally finding their way into homes, congregating on plants and under leaf litter. Unsightly as they may be, these insects are not harmful to humans or their hosts instead they are more of a nuisance than anything else.
The one important feature to note is that these bugs have scent glands located on each side of their abdomen which releases a foul odor when squished.
If you find these bugs unsightly regular use of water from a garden hose sprayed directly on the insect congregations can be effective.