this insect in my garden , on a pine tree and a maple tree and also in the mulch around my flowers and I don’t know if it is an ok insect or if I should get some pesticide to kill it.(Selkirk, Ontario)
You have boxelder bug nymphs, which are the young of the boxelder bug. The nymphs of the boxelder bug have what looks like a yellow spot on the center back of the abdomen. Boxelder bugs do like to congregate together…and they do feed on boxelder or maple trees.
As expected they feed on boxelder trees, rarely causing any economic problem. They are not a pest. They can be observed feeding on ash, maple, plum, cherry, apple, peach, grape and strawberries, where they can damage the fruit.
They are known to be nuisance pests in the fall as they accumulate on the sides of homes. They also seem to manage to come indoors in the fall…which is a nuisance. The time spent in or on our homes, they are not causing a problem.
Since these are outside then you really have no problem. When they become a problem in our homes here in the North we just vacuum them to get rid of them.
They do not bite nor eat anything except maple and boxelder seeds/fruits. No pesticide is needed nor labeled for spraying this insect.
As mentioned by the others you can use soapy water to spray them but a shop-vac is more effective if you have a lot that collect on the side of the house…which will help prevent them from coming in the house.