I had ants and all I did was put all over baby powder! Worked great! I
still occasionally, but rarely see an ant here or there.

I got it from this article:

Here are safer alternatives to commercial pesticides:

Ants: Sprinkle cinnamon, bay leaves, cayenne pepper or baby powder in
problem areas and along baseboards and windowsills.

Cockroaches: Sprinkle equal parts of baking soda and confectioners´ sugar
in problem areas.

Mice: Place cotton dipped in peppermint oil near problem areas. Used kitty
litter is another repellent.

Mosquitoes: Mix 2 teaspoons of apple cider vinegar in a glass of water
placed on your deck or balcony or dab lavender oil on your wrists and
elbows.

Flies: Small sachets of crushed mint placed around the home will discourage
flies. So will a potted sweet basil plant.