Meet diatomaceous earth, a totally natural, non-toxic insecticide.
It’s a fine, white powder which looks something like lime. But whereas lime is calcium oxide treated with water, diatomaceous earth is a soft, sedimentary earth made of fossilized algae. It’s abrasive to the touch, and under a microscope you can see why; it’s made of sharp, glass-like shards. Therein lies its efficacy: sprinkle it around unwanted bugs, and it’ll get into their exoskeleton, abrade the waxy layer that keeps them hydrated, dry them out and kill them dead.
On the other hand, diatomaceous earth is harmless to mammals. While you generally shouldn’t go around breathing it, you can safely dust your dogs, cats and backyard chickens to relieve them of fleas, ticks and mites. You can also dust around your house to repel sugar ants. You can dust your garden rows, too. It doesn’t work if it gets wet, so just make sure to do your dusting when it’s dry.
Food-grade diatomaceous earth can even be eaten, to no harm. Farmers mix this into grain crops to guard against mealworms and other bugs during storage. If you intend to dust your animals or use it around small children, food-grade DE is the way to go.