Does Boric Acid Kill Cockroaches?

Cockroaches are fast becoming resistant to insecticides. So, it’s important to find an effective way to remove an infestation from your home. Boric acid is toxic to cockroaches and several other common household pests.

Boric acid can kill cockroaches due to hydrogen and sodium borate salts (boron). Boric acid can be used in powder, dust, or gel form. If a cockroach eats or makes contact with boric acid, it’ll severely damage its nervous and digestion systems. Over the next 3 days, cockroaches will start to die off.

Cockroaches will carry boric acid back to their nest, poisoning other colony members. To make the formula more enticing, pair it with egg yolks, sugar, flour, or peanut butter. This will lure cockroaches to their eventual deaths.

Does Boric Acid Really Kill Cockroaches?

Boric acid contains active compounds that kill insects with an exoskeleton, including cockroaches.

It harms cockroaches in the following ways:

  • Poisons the digestive system
  • Adversely affects the nervous system
  • Damages the exoskeleton

Boric acid clings to the legs and wings. Its abrasive properties scratch the exoskeleton, causing irreparable damage.

It’s also a poison, so cockroaches will die if they ingest boric acid with peanut butter or boric acid with sugar.

What Does Boric Acid Do To Cockroaches?

When a cockroach crawls through the boric acid, the powder, gel, or dust will stick to its legs and wings.

The powder will get into the digestive system as the cockroach grooms itself. According to the University of California, boric acid can penetrate the cockroach through the exoskeleton’s gaps and spiracles.

Boric acid is slow-acting. Once it gets inside the body, it’ll spread through the nervous and digestive systems. This impedes normal bodily functions, and the cockroach will eventually die within 3 days.

How Does Boric Acid Work?

Boric acid works through direct contact and ingestion. If the poison has to sift its way into the outer shell, it’ll take longer to work. If a cockroach consumes boric acid, it’ll die within 72 hours.

It works by affecting the nervous system. It disrupts the cockroach’s ability to move, balance, and seek out food. It’ll be temporarily paralyzed and flip onto its back. Here, it’ll starve to death or perish from dehydration.

Boric acid targets the cockroach’s digestion, making it impossible to glean nutrients. Because cockroaches are such adaptable insects, one of the only effective ways to kill them is to deprive them of the ability to process energy.

Does Boric Acid Kill All Types Of Cockroaches?

From German cockroaches to American cockroaches, boric acid kills them within 3 days. It’ll even cut the populations of other insects in your home, including spiders and mites.

The abrasive nature of boric acid damages the external structure (exoskeleton) of insects. This causes them to lose moisture rapidly. It also compromises the exoskeleton so that it’s more susceptible to damage.

How Effective Is Boric Acid Against Cockroaches?

Boric acid has been used as an insecticide against cockroaches for decades. According to the Journal of Economic Entomology, boric acid was used in pest control long before synthetic pesticides.

The study found that it’s most effective against German cockroaches. This is true for ingestion and physical contact. Researchers found that ingested boric acid had a 100% mortality rate at less than 0.5% concentrations.

It’s a slow-acting pesticide that takes several days or weeks to kill the cockroach. However, during this timeframe, the affected cockroach may transfer some of the poison to other members of its colony.

Is Boric Acid Paste Safe To Use As A Cockroach Insecticide?

Unlike synthetic insecticides, boric acid paste or powder is a natural product.

It’s extracted from organic chemicals that have been used safely for decades. Besides that, boric acid is found naturally in certain foods we eat, such as bananas, apples, almonds, and peanuts.

However, using boric acid to get rid of cockroaches isn’t entirely risk-free. It can still cause various health problems if you ingest, inhale, or even touch the paste or powder.

Excessive exposure to boric acid can cause:

  • Skin irritation
  • Nausea
  • Headaches
  • Muscle weakness
  • Respiratory problems

Take additional precautions if you share a home with vulnerable adults, young children, or pets.

How Fast Does Boric Acid Kill Cockroaches?

Boric acid is a slow-acting cockroach killer.

In most cases, it can require up to 72 hours for a cockroach to die after ingesting boric acid.

This works in your favor. Once a cockroach comes into contact with the powder, it’ll carry it back to its nest. Here, it will spread it to other cockroaches in the colony by:

  • Rubbing against other cockroaches
  • Leaving behind poisoned feces, which are consumed
  • Dying within the colony and being eaten

When other cockroaches ingest the powder, the chemicals poison their digestive systems and inhibit their metabolisms. Several cockroaches can die once you’ve poisoned just one.

How Long Does Boric Acid Take To Kill Cockroaches?

It takes up to 72 hours for boric acid to kill cockroaches.

If you have a large infestation, you should expect the results to be more gradual. Boric acid works slowly, so it could take weeks or months to significantly reduce the size of a cockroach colony.

Does Boric Acid Kill Cockroach Eggs?

Regrettably, boric acid doesn’t kill cockroach eggs. New generations may remain untouched by the first wave of poison, only to hatch later and continue where their parents left off.

Apply boric acid generously where cockroaches lay and hide egg sacs (ootheca). Once the eggs hatch, boric acid will kill any nymphs that walk over the powder.

What Can I Mix With Boric Acid To Kill Roaches?

Sometimes, boric acid doesn’t work well on its own. Cockroaches aren’t drawn to the scent and may learn to avoid the powder entirely. You’ll need to bait the boric acid with other tempting foods and odors.

Here are some of the most popular options:

Boric Acid And Sugar

To mix boric acid with sugar, combine 1 teaspoon of boric acid with 2 tablespoons of sugar.

The sugar will attract cockroaches. Since boric acid is a fine white powder, they won’t notice the boric acid or its odor.

Boric Acid With Flour

You can also mix boric acid with flour at a 50/50 ratio.

The fine boric acid substance will mix and become inseparable. This forces any cockroaches to ingest the poison with the flower. If cockroaches aren’t responsive to this bait, add some sugar.

If you want a longer-lasting solution, you can prepare this flour-acid mix as a dough. A small amount of water will enable the ingredients to bind together while only taking away some of the boric acid’s potency.

Roll the dough into balls and place them in strategic spots:

  • Along floorboards
  • In corners
  • Under sinks
  • Behind heavy appliances
  • Near electrical motors
  • Around garbage bins

Killing Roaches With Boric Acid And Egg Yolks

Boric acid and egg yolks are good for killing cockroaches. The smell and taste of eggs tempt cockroaches.

Preparing this recipe requires that you:

  1. Place egg yolks in a bowl
  2. Add 1 cup of sugar
  3. Add 2.5 ounces of boric acid
  4. Mix the ingredients to form a thick paste
  5. Create small balls out of the paste
  6. Place the balls along areas where cockroaches like to crawl and hide

Boric Acid And Peanut Butter Bait For Roaches

The scent and fatty texture of peanut butter make it an attractive lure.

Here’s how to make it:

  1. Add 1 part boric acid
  2. To 1 part peanut butter in a bowl
  3. Mix the two ingredients to form a huge ball
  4. Press the mixture into small containers or bottle caps for easy transportation
  5. Place the filled containers or bottle caps in cockroach-infested areas

If you don’t have these ingredients on hand, you can combine the following:

  • Boric acid and beer
  • Boric acid and condensed milk
  • Boric acid, boiled potatoes, and boiled eggs
  • Boric acid and greasy bacon

Can You Put Boric Acid Down The Drain?

Cockroaches like to hide and nest in dark, moist, and undisturbed areas. So, it’s common to find them hiding in the kitchen or bathroom drain.

Since cockroaches cannot survive for more than 1 week without water, they’ll build their colonies near water sources. So, in theory, it makes sense to put boric acid down the drain.

Unfortunately, putting boric acid down the drain won’t kill cockroaches. It’s a soluble chemical that will start to dissolve.

Once dissolved, there’s little chance that cockroaches will ever touch, let alone ingest it. As discussed, boric acid also loses some of its potency when it gets wet.

Boric acid powder can be put in places around the home that cockroaches favor. You can also pair it with baits such as peanut butter, egg yolks, or sugar to attract cockroaches.

Since boric acid kills cockroaches, it can be used as a natural pesticide.

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Jack Andersen

Hi, I'm Jack. A close friend of mine went through a cockroach infestation about 5 years ago, so I'm here to share what I've learned with everyone. I hope that you find the information useful.

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