If you have never heard of the terms ‘boric acid’ or ‘diatomaceous earth’, then the terminology may seem a little daunting, particularly if you are one of those who are (rightfully, I might add) concerned about the overuse of chemical pesticides in our daily life. With our fruits and vegetables already being laced with so many of these chemicals, the last thing we need is more chemicals sprayed around our home to get rid of pests such as roaches, ants, and fleas. And yet, without using chemicals, the question arises: how do we get rid of these pests? Sure, slapping them down with a flyswatter, slipper, or rolled up newspaper most definitely kills them and is also oddly satisfying, but other than emotional catharsis, it won’t really do much to alleviate your problem, especially if your infestation is moderate to severe in scale.
Enter boric acid and diatomaceous earth. Before we go into how we can use these substances to rid ourselves of annoying household pests, let’s delve deeper into what exactly they are and the mechanism of action they use to kill these pests.
Boric Acid – Boric acid is a pesticide, albeit a weak one that is mostly harmless to humans. You might have seen it called ‘Borax’ in your local hardware store. It is a weak, monobasic acid, and while you might think of acids as liquids, boric acid is actually found in the form of crystals or a white to off-white colored powder. To show just how harmless boric acid is, it is commonly used in eye wash products to treat bacterial infections and soothe inflamed eyes. That said, avoid using boric acid in areas where food is prepared (common sense, really).
How does boric acid work to kill pests? Boric acid is slow-acting poison to insects that affects both their stomach and nervous system. The powder itself can also cause abrasive damage upon contact with the insect’s exoskeleton.
Because it is slow-acting, the affected insect will usually be able to make it back to their nest before dying. In the case of cannibalistic insects such as roaches, the dead insect now serves as its own poison as any other insects that eat its body will also become poisoned, creating a powerful chain reaction. This is one of the better ways on how to kill roaches, since it can completely wipe out the roach infestation in your house if you do it properly.
Diatomaceous Earth – Unlike boric acid, diatomaceous earth is a hundred percent natural and also completely non-toxic. Many millions of years ago, there existed single-celled organisms known as diatoms which had a silica transparent outer shell. Diatomaceous earth is the fossilized remains of these diatoms, and while it has many uses, its primary use is as a natural pesticide. You can easily find it at your local hardware store (it’s sometimes marketed as ‘insect dust’); make sure you buy the food-grade kind.
If diatomaceous earth is non-toxic, how does it kill pests such as roaches, ants, termites or other small insects then? Well, it does so via two methods. The first is simply by physical damage; while it looks like fine dust to the human eye, each molecule actually has razor sharp edges that can damage the insect’s exoskeleton. They’re basically little insect knives. The second mechanism of action is dehydration, the microscopic particles of the earth enter the cuticles of the insect’s exoskeleton and begin to absorb the oils and fats from within the insect, drying them out and killing them in the process. Honestly, it sounds like something out of a horror movie; sharp particles that slash you and drain your fluids at the same time, but hey it works!
Methods of Application – Since both diatomaceous earth and boric acid come in a fine powder, their method of application is fairly similar. What you want to do is spread them in a fine layer around typical pest entry points such as cracks and crevices, underneath your fridge or washer, in the void space under your cabinet (you may need to drill small holes into the backs and floors of your cabinets to do this) etc.
The most important thing to note when applying these substances is that less is more; often people make the mistake of applying to much and the result looks more like a clump rather than a fine layer. Put yourself in the perspective of an insect; if you saw a layer of small stones on the road you would probably just walk over it but if you saw a huge pile of stones you would just go around it. Same idea applies here. And lastly, diatomaceous earth is fairly sensitive to moisture, which reduces its effectiveness. Hence, if you apply it in a damp place you may need to reapply it more frequently. Another solution is to use boric acid in the damp places and diatomaceous earth in the dry ones.