Some things in life you go looking for. Others come looking for you.

When you have a cockroach problem, you may not know exactly how they found you, but you’ll be darned if they stick around for long.

What kills cockroaches instantly? We’ve got answers that may surprise you, along with a plan to keep them away for good.

Ready? Let’s get started.

Kill them Fast, But Also Kill Them Slow

Chart illustration using a fast vs slow gauge depicting cockroaches killed with fast methods vs. slow methods

Want roaches gone fast?

You should. They’re nasty, dangerous bugs that can destroy everything you own. They’ll use your home as a dinner plate and a toilet, spreading germs and allergens everywhere they go.

The truth is, roaches can be killed very quickly. At the snap of a finger really, with a number of effective products—some of them off-the-shelf, and some of them homemade.

But there’s also a problem with all these products that their marketing won’t tell you:

If you’re looking for more than a temporary fix, you’re going to have to supplement them with something else.

Sure, you can bomb or spray roaches to oblivion. You’ll see them die in droves.

But these products rarely deal a fatal blow to roaches’ secret weapon—their deeply protected nest. Instant killers aren’t designed for it (no mater what bug bomb pamphlets say). And if you rely on them exclusively, you’ll find yourself in a common cycle: no matter how many roaches you kill, they’ll keep endlessly coming back.

Luckily, there’s a solution. One that kills roaches instantly—just like you need it to, but also kills them thoroughly, so you don’t have to face them again and again . It’s called the fast/slow method, and it combines an instant roach killer with a handful of slow-acting ones designed to remedy the problem at its source.

It gets roaches out of your face right now, and leaves your home roach-free in about 30 days or less.

Sound like a plan? Let’s take a look at the instant roach killers:

What Kills Cockroaches Instantly: Home Remedies and Powerful Pyrethroid Sprays

1. Pyrethroid-Based Sprays: The Big Guns

Cartoon illustration of a shocked cockroach being sprayed on a kitchen counter with a can of pyrethroid spray.

Ah, pyrethroids. Where would all those dead bugs be without you?

Medicine has penicillin. Basketball has Michael Jordan. And pest control has the amazing family of pyrethroids, chemicals naturally and synthetically derived from chrysanthemums that clock roaches with a mighty wallop.

Mostly safe for humans (but less so for some pets—read up to understand the cautions), pyrethroids attack insect nervous systems, stopping (known as “knockdown”), and quickly killing roaches in their tracks.

In use since the 1940’s, you’ve probably already used or been helped by pyrethroid sprays. Popular products like Raid, Combat, Black Flag, and Ortho sprays have long relied on pyrethroids to do the job.

Is every pyrethroid spray you find an instant killer? Yes. Pretty much. Unless you find some sort of off-brand (and there aren’t very many of them), you can be confident that most any pyrethroid-based spray is going to be fairly lethal.

There are differences in formula however that make certain pyrethroid-based products more effective. And as you might expect, the most effective ones tend to be the most expensive.

At the high end, you’ll find professional products you may not even be able to get your hands on as a consumer. While a notch or two below, higher-end consumer products, like Bengal Gold (which has gained a sort of cult following among its users) are widely sold.

Beyond their near-instantaneous roach killing abilities, pyrethroid sprays provide an important side benefit—”residual” properties that make sprayed surfaces toxic to roaches for days or weeks depending on which formula you buy.

2. Essential Oils: Natural Cockroach Killers

Cartoon illustration of an angry cockroach, shaking its fist at a bottle of essential oil.

For those unfamiliar with the science behind essential oils, you may be surprised to learn how intensely studied they’ve been across numerous different fields. Pest control is one of them, and the research has been impressive.

Certain essential have been proven to be effective against roaches. Some have repellent properties, some kill roaches on contact, and some do both depending on how much of them you use. Sufficiently concentrated, some essential oils kill roaches almost as fast as pyrethroids.

And in practice, that’s going to be your key to making them work. You need to hit roaches with a high dose, and need to hit their bodies with it directly.

Most essential oil products aren’t going to do that for you. Aromatherapy candles and diffusers deliver an airborne dose that’s far, far too weak. And if you plan on using a spray, you’ll generally need a high concentration. Not 100% because your sprayer’s going to clog, but 2% or more (depending on the oil).

The oils that work? Peppermint, clove, rosemary, and thyme have proven lethal properties. You can either make your own “instant roach killer spray,” or use a packaged product like Zevo or Wondercide.

To learn more about essential oils for roaches click here.

3. Surfactants: Cheap, Safe, and Believe It or Not, They Work

Cartoon illustration of a dead cockroach in a bathroom covered with soap bubbles.

What kills cockroaches instantly (well, almost), and so cheaply it might seem too good to be true?

Household surfactants.

Surfactants are compounds that reduce the surface tension of water, making it spread out more uniformly.

They’re found in soaps, hand and dish detergents, fabric softeners and toilet bowl cleaners. And when you make surfactants sprayable by combining them with water, they become deadly to roaches, blocking the pores they need to breathe.

Surfactants don’t exactly kill roaches instantly, but do accomplish it within several minutes.

Unlike pyrethroid products, which take very little to quickly kill a roach, you have to seriously douse cockroaches with surfactants to achieve the same effect.

You’ll also find surfactants work better on certain roaches than on others. For instance, German roaches give up the ghost pretty quickly under a blast of surfactant, while American roaches… not so much.

Of the various surfactants used to kill cockroaches, soap and sodium lauryl sulfate (SLS) are the most common, with SLS being the most tested and proven of the two.

For soap products in a spray bottle, you’ll find products like Aunt Fannie’s Roach Remedy which combines soap with a few essential oils.

For SLS formulas, check out Ortho Home Defense Spray and Eco Defense Home Pest Control Spray

4. Sticky Traps: Eliminate Cockroaches Overnight

Cartoon illustration of a cockroach on a kitchen counter, stuck down with sticky glue.

Less dramatic than instant cockroach killer sprays, sticky glue traps may not kill roaches instantly, but they often do it overnight. Depending on the severity of your problem, you could set up these unassuming killers before you go to bed, and find them full of roaches by morning. They’re highly respected in the pest control world, and for good reason: they work.

When using sticky traps for general purpose killing, you’ll want to place them where you suspect cockroaches have been crawling and congregating—along baseboards, behind appliances, under furniture and in pantry areas. Then check them every once in a while for what they’ve caught.

You’re probably familiar with roach motels, which are fine for this approach. We’ll tell you another trick with sticky traps in the next section, because they’re an excellent slow-kill pest control tool, too.

For more about using sticky traps, click here. To learn more about roach motels, click here.

5. Foggers and Bombs: Forget About Them!

Cartoon illustration of a cockroach laughing at a defused roach bomb

Roach bombs and foggers. Who doesn’t love them? Are they fast? You bet they are! Full of drama and excitement? Oh yeah—the kind that sells lots of products.

Unfortunately, they don’t work too well, so seriously—don’t fall for them. They’ll impress you with the scores of dead bugs they leave behind, but those massive clouds of pesticide? They’re far from laser-guided and won’t penetrate the hard-to-get-to nooks and crannies you’d definitely need them to.

To learn more about cockroach bombs and why you may want to choose something better, click here.

What Kills Roaches Slowly: The Long-Term Prescription

Here’s the most basic fact about getting rid of cockroaches: They’re easy to kill individually, but hard to completely wipe out. They’re little survival machines, not so much as individuals, but in their ability to rebound against you as a group.

That means roaches are sneakier and more trickier than you might think. And to truly wipe them out, you’ll need some trickery of your own, including several tricks up your sleeve to completely finish them off.

Professional exterminators know this. That’s why over the last couple decades or so, they’ve moved more and more away from fast-kill interior sprays, toward the slower-acting products described below.

These products may not leave roaches sputtering around your kitchen within seconds. But they do kill with a thoroughness and level of safety that was never possible before.

Having learned what kills cockroaches instantly, let’s move on to the ones that used together, slowly wipe them out:

1. Sticky Traps: Useful for Slow-Kill, Too

Sticky traps aren’t just effective killers. They’re peerless information-gathering tools. By setting them out systematically and then counting the roaches that you’ve caught, you’ll learn not only how bad the problem is, but where it’s worst. Which tells you where to hit the bugs the hardest.

The technique is known as “monitoring,” and it’s the first best way to take control of a cockroach problem. To use sticky traps this way, you’ll need to also do some simple record-keeping (as in recording where you’ve placed them).

You’ll also want to buy sticky traps sold in larger packs (which end up being cheaper), and that make examining contents and recording information easier.

Learn more about finding cockroach hiding spots by clicking here.

2. Gel Baits: Wipes Out the Colony Over Weeks

With a week or so of “monitoring” various places in your home, you’ll know where to place a game-changing product known as cockroach gel bait.

Sold in syringes and plastic bait stations, gel baits can be astonishingly effective. They lure roaches with a powerful attractant, then kill them with a slow-acting insecticide after they eat it.

The slowness of gel baits works to your advantage because roaches have time to return to the highly populated nest. When they eventually die there, other roaches will find and eat its body, ingesting some of the poison, too. Over time, many roaches will die from a single tiny dose of poison, and possibly the entire nest.

Learn more about using cockroach gel bait here.

3. Insecticidal Dust: Applied Once, Lasts for Years

The third slow roach killer is a fine powder called insecticidal dust. Sold in natural and man-made forms (like silica gel, diatomaceous earth, and boric acid), “dust” is puffed deeply into cracks and crevices with a tool called a “hand duster.”

When roaches crawl through the light dusting, it sticks to their bodies and slowly destroys their shells. Like gel bait, the slow acting nature of insecticidal dust makes it more effective, because roaches never learn that it’s something to avoid.

Dusts don’t expire or degrade, so a single application could begin killing roaches right now, then help protect your home for years.

You can learn more about insecticidal dust by clicking here.

4. Insect Growth Regulator (IGR): Stops Future Roaches

Insect growth regulator (IGR) isn’t exactly a killer. Instead, it prevents young roaches from becoming fertile, halting future generations. Since baits, dusts, and traps are so effective, it could be considered an optional product, but if you have a true cockroach infestation, you should plan to pick some up.

5. Outdoor Products: Killing Roaches Before They Get Inside

Have outdoor roaches?

Outdoor products are mostly similar to indoor ones, but hold up better in outdoor conditions. There are slow-acting outdoor baits made specially for lawns, and a variety of outdoor liquids for the perimeter around your home. One of the advantages of these liquids (which are applied with a specialized pump sprayer), is the ability to mix products for simultaneous slow and fast-acting results.

Using Slow and Instant Cockroach Killers Together

Keeping Products from Working Against Each Other

If you’ve decided the fast/slow method is better than simply reaching for a can of spray (it is), you may already be making a purchase list. Good for you.

You can go ahead and order your slow-kill products. But before settling on the instant one, one suggestion:

Some instant cockroach killers leave a repellent residue behind. And while that may be great for keeping roaches away from your cupboards when you can’t stand the sight of them, it’s lousy when the little monsters begin avoiding your dusts, baits, and traps.

To keep your slow-kill products working the way they’re supposed to, you’ll either want to avoid products that contain repellents, or limit them to areas well away from your slow-kill products.

Tip: It’s also possible to strategically use repellent products to drive roaches toward your baits, dusts, and traps

Which products have repellent properties? Virtually all essential oils do, as well as some sprays. So before smashing the buy button, you should do a little quick label-reading (most product labels are available online) to see what’s coming in the can.

Hitting Problem Areas

Drains

There are certain problem areas you may need super fast results. Drains are one.

If roaches are truly coming up your drains from the sewer (not as common as you might think), you should first make sure that the little bend beneath your sink (called the P-trap) is filled with water. It provides a barrier that keeps roaches and other things out. Drain covers will serve that purpose, too.

For an instant kill, use bleach or a foam drain killer, but be extremely careful about mixing up your own potions, which could damage your pipes or worse—poison you along with the roaches, in a homemade toxic cloud.

Conclusion

While there’s nothing like a little murder spree to get you started, it’s only half the way to win the war. Because the real battle against roaches isn’t won quickly—it’s won slowly. With the right approach and a few of the right tools.

You’ve learned what kills roaches instantly and what kills them slowly. Now go ahead and get rid of them for good.


Sources

  1. Kato, Yuki, et al. (2019) Measurements of the Hansen solubility parameters of mites and cockroaches to improve pest control applications. Heliyon. Retrieved from https://www.sciencedirect.com/science/article/pii/S2405844019336060
  2. Sodium Lauryl Sulfate (2014) Health Canada Pest Management Regulatory Agency. Retrieved from https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/cps-spc/alt_formats/pdf/pubs/pest/_decisions/rd2014-03/rd2014-03-eng.pdf
  3. Ramsay, Kris. Common Household Products That Contain Nonionic Surfactants. Hunker. Retrieved from https://www.hunker.com/13420814/common-household-products-that-contain-nonionic-surfactants
  4. Appel, Arthur G., et al (2001) Repellency and Toxicity of Mint Oil to American and German Cockroaches. Department of Entomology and Plant Pathology, Auburn University. Retrieved from https://www.ortho.com/en-us/products/bugs/ortho-home-defense-max-ant-roach-spider1

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