Non-toxic Pesticides? Unraveling The Claims

We probably all agree that there are some living things we can readily call “pests”. They may be bothersome bugs that scurry around in our homes, insects that feed on us by sucking our blood, insects that damage our plants by eating the leaves or destroying the trunk of the tree, or rats and mice that choose to live inside our homes. They may even be weeds growing in your lawn or nicely landscaped garden. Whatever your level of tolerance is for these kinds of creatures living near you, there will be times you decide that they need to go. Here is where we begin to find widely differing opinions on how to accomplish the task, and what materials to use. Often the most effective and expedient material is some kind of pesticide, whether that pesticide is for weeds, rodents, or insects, and choosing the proper material should take into account any hazards it may pose to you, your pets, and the general environment around you.

This article is not intended to argue the question of whether or not pesticides “should” be used, but instead to discuss the claims made about pesticides offered to you. Quite often you will find advertisements proudly stating that their product is “100% non-toxic” or “safe to use around children”. Could there be such a thing as a Non-Toxic pesticide? No, not really, and yet we readily can find such claims on the internet, in magazines, and on store shelves. One website that advocates the use of boric acid for insect control makes these claims.

  • It is safe to use around children
  • It is non-toxic to humans
  • It is deadly to all insects
  • It is the secret ingredient in many commercial treatments
There were other statements on this website that were equally false, but let’s look at these four a moment to use this product as an example, for boric acid is a very popular insect control material, and widely advocated as a substitute for those “toxic pesticides”. It also is a very good active ingredient that can be effectively used for many kinds of pest insects.

Considering the last statement first, there is no such thing as “secret” ingredients in pesticides used by the pest management industries. The products they use are well known and you have the right to know everything about them that you choose to know. The professional company wants you to understand the processes they will use, and wants you to be comfortable with any pesticides they may use on your property. It would be illegal for a pest management professional to refuse to tell you what he or she is using, and many states require this information to be provided in advance and in writing.

The statement that boric acid is deadly to all insects is also incorrect. Boric acid must be eaten by an insect for it to have any effect, and insects such as mosquitoes, adult fleas, and bedbugs have no mechanism for ingesting this powder. Instead of using jaws (mandibles) to gather food and grind it up for swallowing, many insects use a straw-like mouth (a proboscis), and thus are obligated to ingest only liquids. They do not groom themselves and have no other way to get that boric acid into their stomach, and simple contact with the dust is not going to affect an insect.

But, it is the other two statements from this particular website that are the most troubling and most dangerous. Boric acid is sold for pest management in many forms now, including as a dry dust that can be applied into enclosed voids where insects may be hiding. It also is used in a great many insect bait products, principally for ants and cockroaches. A short lesson on measuring toxicity goes like this. The toxicity of chemicals in general is measured as the LD-50 of that material, and this stands for the “lethal dose to 50%” of the animals tested in a laboratory setting. By determining this toxic level the various products can then be compared, rating them from Highly Toxic to Slightly Toxic. This LD-50 is not just reserved for pesticides, but you can find the information for virtually all household products that you may commonly use – aspirin, bleach, window washing fluids, gasoline, laundry detergent.

Yes, at some level of exposure EVERY material will have a toxic effect on people, including water. Some are simply more toxic than others, meaning those products that are more toxic would be hazardous at a lower level of exposure. If we compare the relative toxicity of some pesticides to these household materials we find that many of the popular insect control chemicals have a toxic level very close to that of aspirin or table salt. This is not to suggest that we should feel comfortable eating those pesticides, but by the same token we also would use care when taking medicines or vitamins, knowing that to take too many can make us ill (a toxic effect). In addition, most pest control chemicals are greatly diluted with water or some other carrier, and used at extremely low concentrations of the actual active ingredient. This also lowers the relative toxicity of the material applied around your home or garden.

Focusing again on boric acid, it turns out that the toxicity of pure boric acid is similar to the toxicity of aspirin, and boric acid dust sold as a 98% concentrate could, potentially, be dangerous when used improperly. A teaspoon of that dust could be a serious health threat should a child eat that amount. For this website to state that boric acid is “non-toxic to humans” and “safe to use around children” invites misuse. Like any other pest control chemical, boric acid is very useful when applied properly and according to the directions on the container’s Label, but dangerous if dumped in piles around in the home where infants or pets might find it and put it in their mouths.

Everything can be toxic and everything can be used in a safe manner, and this is the distinction. We would no more take 50 aspirin for a really bad headache than we should use too much insecticide in a spray tank. Somehow we recognize that taking too much medicine is foolish, but we may bend the rules when it comes to killing bugs, and this is not necessary. Manufacturers spend tremendous amounts of money to determine exactly how much is needed, and doubling or tripling the recommended dose is not going to kill a cockroach twice as dead.

So, be careful, and challenge information that does not seem realistic. There are many pesticides that have a very low relative toxicity, and you can get a hint of that by reading the product Label. Those products that have a bold “CAUTION” as the signal word are telling you their hazard is lower than those that say “WARNING”. Many of the plant-derived insecticides have a lower hazard, but they still have a toxic level, so even these must be used properly and according to directions. These may include many familiar active ingredients, such as garlic, clove, rosemary, mint, or lemon oil, and accompanying claims may state they are not toxic. But, they are. It is entirely dose dependent, and you or your family could be harmed by these if they are misused.