Can Roaches Adapt to Boric Acid? – The Surprising Answer

A roach infestation in your home is definitely unsettling and something you want to end as soon as possible.

One of the common go-to solutions in such situations is boric acid. While boric acid often tends to work great at the beginning, it tends to appear less effective over time. Today, we look into the roots of this phenomenon. 

So, can cockroaches really adapt to boric acid?

Yes, they can. Cockroach populations can develop resistance to different insecticides extremely fast. Not only this, but they can also learn to avoid the poison even faster. 

How come cockroaches develop an immunity to our attacks so fast? And what can we do about it? You probably already know that roaches are extremely resistant, but what makes them so strong? Let’s dive in! 

Do Cockroaches Become Immune to Boric Acid?

Yes, cockroaches have the ability to evolve resistance to boric acid as well as any other substance known to kill them. German cockroaches – the kind that is most common in apartment buildings, has been shown to be especially adept at this. 

While scientists don’t yet know how cockroaches manage to evolve so fast, it is certain that they do. It is a process similar to bacteria developing resistance to antibiotics, something that we’ve all probably heard about. 

One thing should be clarified here, though. A single cockroach cannot develop immunity to boric acid. The development happens genetically, through evolution.

The thing is – cockroaches reproduce really fast, and while the first generation might not be resistant to boric acid, the next generations can already start developing immunity. 

Do Roaches Learn to Avoid Boric Acid?

Recent research shows that cockroaches are capable of learning and remembering information. However, it is highly unlikely that a single cockroach could learn to avoid boric acid. This is due to a simple reason: cockroaches that come in contact with boric acid usually die, so there is no space for the bug to figure out it shouldn’t touch boric acid. 

However, cockroach populations can actually learn to avoid certain substances. Just like with boric acid resistance, this happens through evolution.

The mechanism is simple – if in a population of cockroaches there were some who had an aversion to boric acid, they could be the only ones to survive. This avoidance trait is hereditary, which means the next generation of roaches will likely be more avoidant of boric acid.

This usually doesn’t happen, though, since the roaches are usually not attracted to boric acid. Rather, they are attracted by the bait you mix with the acid, and they can learn to avoid this substance over a couple of generations – if they survive. 

What Can You Do to Make it Harder for Roaches to Adapt?

No one can really control the adaptive mechanism of cockroaches. However, there are some tactics you can use to make the fight more effective. The key is getting rid of all of the cockroaches as fast as possible, before they have time to adapt to boric acid (or whichever other insecticide you are using). 

Here are some tips to make boric acid more effective against cockroaches: 

• Do not use too much boric acid. If you simply dump a pile of boric acid on the floor, the roaches can very easily avoid it, and it is very likely they will. What you want to do is create a layer of the powder that is as thin as possible. If your boric acid came in a squirting bottle (it usually does), be careful how you handle it. Alternatively, you can use a brush or a duster to spread the boric acid in a fine layer.

•  Place the boric acid in the right spots. Cockroaches like to move in the dark. If you are trying to get rid of roaches, you’ve probably already faced the phenomenon of coming into a dark house and turning on the light only to see a swarm of cockroaches. If this has indeed already happened, make sure to apply lots of boric acid around this area. Other than that, try to get into every dark corner around your house. Inside the cabinets, under the refrigerator, behind the stove – these are some good places. Wherever you see a crack or a nook where a cockroach could hide, dust it with boric acid. Again, the key is to trick as many roaches as possible as fast as possible to touch the powder. 

• Do mix the boric acid with cockroach bait/food. Cockroaches are not naturally attracted to boric acid, so you’ll want to include something else to attract them. You don’t necessarily need the roaches to eat the boric acid – it is enough for the powder to stick to their body. However, the bait is a good idea because it helps attract them to the right place. 

You can find more information on what to use as bait below. 

Are Some Mixtures of Boric Acid and Food Harder for Roaches to Adapt to?

No, there is no evidence that certain foods are harder to adapt to. This is due to the adaptive mechanism of cockroaches we described above. Every kind of bait works if it attracts cockroaches, and if it does there is the same chance the roach population will learn to avoid this bait any other they would be attracted to. However, this does not always happen, and your best bet is definitely to eradicate the roaches before they get a chance to adapt. 

Should You Rotate the Bait (Food) to Keep the Roaches Guessing?

If your bait seems to be effective (i.e. you see dead cockroaches), then there is actually no reason to change the bait. Rotating the bait preventively is not necessary, as long as the bait you are using works.

If it starts looking like the bait is less effective, it might be a sign that the roaches have developed resistance to this particular bait. In that case, it’s time to switch and try something else. 

Related Questions

How long does it take for boric acid to kill roaches?

If the cockroaches have taken the bait and came in contact with boric acid, the results (in the form of dead insects) should be visible within a day or two. If they ingest boric acid, cockroaches that have not developed a resistance to it will surely die within 72 hours. 

Does boric acid kill roach eggs?

No, boric acid does not kill cockroach eggs. However, there is a high likelihood that the insects that were in contact with boric acid will bring it also to the vicinity of the eggs. If the nymphs come in contact with boric acid after they hatch, they will be killed immediately. 

How fast do roaches multiply?

This will depend on the type of cockroach as their reproductive cycles can be different. In general, a female cockroach can produce approximately 8 egg cases in a lifetime (up to a year). Each of these cases will contain 30 to 40 eggs. This means a single cockroach can produce more than 300 offspring within a year. However, the offspring will also start reproducing in this period which means the number would become much higher if the roaches are left alone in favorable conditions. The short answer is: they multiply really fast. 

For more info on dealing with roaches, you might want to check out these guides:

The complete guide to getting read of cockroaches

Boric acid and peanut butter as bait

Do dead cockroaches attract more cockroaches?