Boric acid is a commonly recommended home remedy for pest control by many DIY experts. In this comprehensive guide, we’ll cover everything you need to know about boric acid, including its mechanism of action, preparation methods, safety considerations, and possible alternatives.
Boric Acid vs Borax
When looking for DIY pest control remedies, you may come across terms such as boric acid, boron, borax, and borate salts. While these terms may seem interchangeable, they are not the same thing.
Boric acid is a type of acid that contains boron and is typically found in the form of a white powder that can dissolve in water. It is created through chemical reactions between borax and mineral acids.
On the other hand, borax is a mineral that also contains boron. It is also referred to as sodium borate or borate salt. It is commonly used in household cleaning products such as detergents and soaps.
While both boric acid and borax can be used to eliminate insect pests, they are not interchangeable. It’s important to note that boric acid is more potent and toxic than borax and should be handled with caution.
Understanding How Boric Acid Works
The precise mechanisms by which boric acid and borax eliminate insects are not fully understood. However, we do know that they work in two main ways: oral ingestion and contact.
Insects can be killed by directly ingesting boric acid or borax. Boric acid disrupts the foregut, one of the three sections of the insect gut, causing insects to die of starvation within a few days of ingestion.
Both Boric acid and borax can be used to kill pests.
Are Boric Acids Safe to Use?
Featured in many DIY pest control blogs and videos, boric acid and borax are relatively safe to use. However, borax can corrode eyes via contact, causing irreversible damage.
While boric acid and borax powders are effective in killing insects, don’t use them to treat pests in the powder form. This is because the powders are very fine. They can drift in the air, and become an inhalation hazard, or contaminate food.
Please bear in mind that anything can be toxic, as long as the concentration is high enough. For instance, salt has an oral LD50 of 3 g/kg. That means 50% of humans who weigh 70 kg will be killed if they consume 210 g of salt (3 g/kg is 210 g per 70 kg). Even though salts are safe to be consumed at a normal level, over-consuming salts can kill.
The same applies to boric acid and borax. While they are generally safe, they can kill at high dosage. According to the EPA, 3-6 g of boric acid can kill a child if ingested.
The issue with DIY remedies (not limited to boric acid) is the lack of information on safety precautions. If you buy a legitimate synthetic pesticide, the label tells you how to use it safely. With home remedies (in this case boric acid), you are on your own!
Should I Use Boric Acid or Borax for Pest Control?
Use boric acid instead of borax for DIY pest control, because borax is highly corrosive and can damage eyes. Efficacy-wise, there aren’t any significant differences.
What Pests can I Kill with Boric Acid?
Boric acid is typically used in bait formulations to kill ants and cockroaches. The killing speed is generally slower than other commercial products.
Boric acid can also kill fleas, spiders, and other insects when applied as dust. However, there are better non-toxic products available in the market for the same purpose.
Boric Acid Bait Recipe
Add 2 g of boric acid and 20 g food matrix in a measuring cup. For ant bait, add warm water until the final volume is 100 mL; for cockroach bait, add 30 mL warm water instead. You can use table sugar, peanut butter, egg yolk, fruit jam and honey as the food matrix. Stir the mixture until the additives are dissolved.
Following this recipe, the resulting ant bait is a boric acid liquid, while the cockroach bait is a slurry paste.
A typical bait contains 2 elements: the toxicant and the food matrix. Toxicant is what kills the target pests (in this case, boric acid) while the food serves as a medium to carry the toxicant so that it is ingested by the target pests.
The key challenge here is to deliver the right amount of boric acid to the target pests and choosing the right food.
If the amount of boric acid used is too low, it doesn’t kill the pests. If too much is used, the pests will find the bait unattractive. Similarly, if you choose the wrong food, the pests will just ignore the bait.
Deciding the Food Matrix
First thing you need to do before making a boric acid bait is pre-baiting. Apply some peanut butter or egg yolk near the pests (eg. ant trail) and observe whether the ants are attracted. If the ants ignore the peanut butter, try sugar-based food such as fruit jam, sugar syrup or honey. They are usually attracted to either one.
It is rather difficult to observe the food preference for cockroaches, though. Either the roaches run away when you approach it, or you may run away if they approach you. That’s why we recommend using commercially available bait for roaches.
Applying Boric Acid Baits
To bait ants, place a few drops of the bait along the ant trail. Repeat the treatment every few days until the population is eliminated. It took us close to 2 months to suppress a pharaoh ant colony in a room.
To bait cockroaches, place multiple dabs of bait at places where cockroaches are hiding to increase the chances of them encountering the baits.
After baits are applied, do not spray anything that can make the bait less palatable, especially repellents.
Adjusting the Boric Acid Concentration
Once you know which food is more attractive, you can start making the bait. For ants, the concentration of the boric acid should be between 0.5-2%. The more palatable your food is, the higher the concentration of boric acid you can put.
The recipe above produces 2% ant bait. If the ants ignore the bait even though you are already using the preferred food matrix, try lowering the amount of boric acid in the recipe from 2 g to 1.5 g.
Please wait 10-15 minutes before you conclude whether the ants are attracted to the bait. Sometimes, due to insufficient workers, the ants will leave the bait just to recruit more ants.
What are the Alternatives to Boric Acid Remedies?
Other than boric acid, there are other non-toxic or low toxic products that you can use to address your pest issue.
Diatomaceous Earth
Diatomaceous earth is a natural, non-toxic substance that effectively kills insects upon contact. It works by damaging the cuticle of the insects, causing them to lose excessive amounts of water and ultimately die.
It’s important to purchase diatomaceous earth specifically formulated for pest control, such as Nature Guard Diatomaceous Earth. The diatomaceous earth powder in such products come in the right particle size effective for pest control.
One potential downside of using diatomaceous earth is that it’s in powder form, which can pose an inhalation hazard and risk of contamination. Therefore, it’s crucial to apply it with care and precision.
However, it’s worth noting that while diatomaceous earth can eliminate individual ants, it doesn’t address the issue of the ant colony. To fully resolve an ant infestation, it’s necessary to target and eliminate the entire colony.
Plant Extracts and Essential Oils
Another alternative is plant-based products such as pyrethrins, pyrethrum, cedarwood oil, citronella oil, and other essential oils. Similarly, buy those labeled for pest control use, such as Nature-Cide. Those meant for aromatherapy may not have the right concentration to kill pests, and they can be quite expensive.
Certain manufacturers may have formulations that make their plant-based pest control products last longer after application. Such formulation is generally not used in aromatherapy essential oils.
Note that such products kill pests only through direct contact. Once it dries up, it may leave an odor that chases away the pests. Such repellency is typically insufficient to achieve effective pest control.
Ready-to-Use Baits
If DIY baiting is too much a hassle, you should consider using commercially available baits. Here are some of my recommendations.
Terro Liquid Ant Bait
Terro ant bait is a sugar-based ant bait containing borax, a compound commonly used in household cleaning products. It comes in a ready-to-use package, and saves you the hassle of preparing your own DIY bait. Similar to boric acid bait, repeated application is required to eliminate the colony.
Advance 375A Select Granular Ant Bait
Advance 375A Select is a protein-based ant bait. It contains naturally-occuring abamectin that can slowly kill the ants, and eliminate the ant colony.
Vendetta Plus Cockroach Bait
Vendetta Plus is a professional cockroach control bait. It contains 2 active ingredients: abamectin and pyriproxyfen.
The naturally-occuring abamectin kills the roaches upon ingestion. Meanwhile, pyriproxyfen is a synthetic component that mimics the hormone found in insects. It is very effective in killing baby roaches by disrupting their growth.
When baiting roaches, be sure to place the baits at multiple locations to increase the chance of the roaches encountering the bait.
Final Words
Achieving success with boric acid baiting requires a great deal of patience and some trial and error. If you’re dealing with stubborn pest problems that need to be addressed quickly, I recommend checking out my blog for a variety of effective methods to get rid of different types of pests.
Additionally, be sure to read my article on the best DIY pest control products, as well as products that should be avoided. With the right tools and knowledge, you can effectively tackle your pest issues and enjoy a pest-free home.
