⚡ TL;DR: Quick Summary
- Moth balls only repel roaches temporarily by smell, they don’t kill them, and they’re a registered pesticide meant for sealed containers, not open kitchens.
- Pepper spray, cedar, mint oil and bay leaves can discourage roaches with strong scents, but none of them address the source of an infestation.
- Cedar has some genuine scientific backing against cockroaches, though it works best in small, enclosed spaces rather than open rooms.
- Perth’s warm climate suits German, American and Australian cockroaches, and it’s not just a “dirty house” problem, roaches move in wherever they find food, water and shelter.
- Repellents can buy you time, but if roaches keep reappearing it usually means a colony is already established somewhere they can’t reach, and that’s when a professional inspection makes more sense than another home remedy.
Repelling cockroaches is one portion of an integrated pest management solution for ridding your home of cockroach infestations. If the roaches don’t like the environment of your home, they are less likely to enter and nest in the first place. If you can find roach repellents that don’t also repel all the humans you know – even better.
The following 5 roach repellents might just do the trick to make your home the last place a roach wants to live:
Pepper Spray – Roaches don’t like red pepper. So, if you spray surfaces in your kitchen and bath with a solution containing red pepper, the will avoid those surfaces. An easy recipe to whip up a batch of spray is to mix 2 tablespoons of Tobasco Sauce (the primary ingredients are red pepper and vinegar) with 1 quart of water. Pour it into a pump spray bottle and mist it onto surfaces. A word of caution, you will be misting pepper spray into the air. Until the mist settles, you are likely to sneeze more than a few times. Consider wearing a mask when you apply the spray.
Pepper’s heat compound has a long folk history as a roach deterrent. There isn’t the same depth of formal roach-specific research behind it as there is for cedar, but it works on the same basic principle: strong, irritating scents make roaches divert around a treated surface rather than cross it.
Moth Balls – Roaches, like moths, don’t like the smell of moth balls. One common remedy is to drop a couple moth balls behind the stove to keep the bugs from hanging out back there. One or two in the cabinet under the sink can be helpful as well. Moth balls are not good for humans, so don’t place them near food or food prep areas.
Do Moth Balls Actually Keep Roaches Away?
This is one of the most-searched questions we see, and it deserves a straight answer: moth balls will make roaches want to leave an area, but they will not solve a roach problem on their own.
Moth balls are a registered pesticide product, usually made from naphthalene, and they’re designed to slowly release fumes strong enough to deter fabric pests like moths in a sealed space such as a storage container or a suit bag. Roaches share the same dislike of that smell, so a moth ball tucked behind the stove or under the sink can make roaches steer clear of that exact spot while the smell lasts.
What moth balls will not do is kill an existing colony, get rid of eggs already laid in wall cavities, or stop roaches from simply relocating a few centimetres away to a spot without the smell. That’s the gap between “repel” and “eliminate,” and it’s the reason so many people who try moth balls end up seeing roaches again within a week or two.
There’s also a safety side to this worth taking seriously. Moth ball labels specify enclosed spaces for a reason. Left out in the open in a kitchen, pantry or living area, the fumes can build up to levels that irritate eyes, noses and airways, and moth balls are frequently mistaken for lollies or treats by young children and pets. If you use them at all, follow the product label exactly and keep them well away from food preparation areas, kids’ rooms, and anywhere a pet could reach.
Repel, Kill, or Prevent? Three Different Jobs
🌿 Repel, makes roaches avoid a specific spot because of smell or irritation. Moth balls, cedar, mint oil, bay leaves and pepper spray all fall into this category.
💀 Kill, actually ends a roach’s life, usually through poisoning, dehydration or physical damage. Boric acid, diatomaceous earth and professional baits do this.
🔒 Prevent, stops roaches from having a reason to come inside in the first place by removing food, water and entry points. This is the only category that stops a problem from starting.
Cedar Products – The oils in cedar wood are an effective natural deterrent for a host of bugs. There are many products available to take advantage of this fact. Look for thin cedar veneers that can be used to line drawers and cabinets, cedar balls, blocks, chips, etc to place in drawers and closets, and (of course) cedar boards and paneling to line closet walls for the ultimate protection.
Of everything on this list, cedar has the most genuine scientific support. Laboratory testing on German and brown-banded cockroaches has shown that cedar panelling does measurably repel them, and the effect strengthens the more cedar surface area the roaches are exposed to. That said, cedar’s strongest results are against moths and other fabric pests, with cockroaches showing a more modest, less complete response, particularly once you move from a small enclosed drawer to an open room.
Mint Oil – Mint oil is a primary ingredient in several non-toxic roach sprays. The roaches avoid it, and when coated with it, they suffocate. The sprays don’t kill as fast as typical poisons, but they are safe to use in the kitchen and around pets and children. It is possible to create a spray, like the pepper spray, by diluting some Dr. Brauner’s Peppermint Castile Soap in water and then applying with a spray bottle. I haven’t tried it, but you might be able to create your own roach spray this way if the soap concentration is high enough.
Peppermint oil is one of the more commonly tested “natural” repellents, and menthol is understood to interfere with the sensory receptors roaches use to navigate, which is why a peppermint spray can genuinely disrupt roach movement through a treated zone for a period of time. Like the other scent-based options here, it fades as it evaporates or gets wiped away, so it works best refreshed every week or two rather than applied once and forgotten.
Bay Leaves – Bay leaves are another sent that roaches avoid. You can pick up a bunch of dry bay leaves in the spice section of any grocery. Place whole leaves or small sachets of crushed leaves in closets and cabinets. This is a good option for kitchen cupboards.
With the exception of moth balls, there are no hazardous chemicals in any of these roach repellents. Give them a try, in combination with baiting, sealing, and applications of diatomaceous earth and boric acid to eliminate roaches from your home.
How To Apply Any Of These Repellents Properly
Identify the exact spot, behind the stove, under the sink, inside the wardrobe, where you’ve actually seen roaches or droppings, not just anywhere in the room.
Clean the area first. Wipe away food residue, grease and dust so the repellent’s scent is the strongest thing in that space.
Apply the repellent directly at that spot, and reapply or replace it every week or two as the scent fades.
Which Roaches Are You Actually Dealing With In Perth?
Repellents work differently depending on which roach you’re up against, and Perth’s warm climate happens to suit several species. The three you’re most likely to encounter around Rockingham, Baldivis, Mandurah and the wider Perth metro area are:
German Cockroach
Small, light brown, with two dark stripes down the back. Breeds fast and prefers warm, humid spots close to food, kitchens, behind fridges, under sinks, exactly where repellents like moth balls and cedar sachets tend to get placed.
American Cockroach
The largest of the three, reddish brown with a pale band behind the head. Often found in subfloors, drains and roof voids. Because it ranges further outdoors, a scent barrier at one entry point may just push it toward another.
Australian Cockroach
Mostly an outdoor species that shelters in mulch, garden beds and leaf litter, moving inside when the weather cools or food gets scarce outside. This is one reason a repellent placed only indoors can miss where the roaches are coming from.
Related → Cockroaches in Perth, Australia | Common Australian Cockroach Pests, Types You Should Know
DIY Repellents vs Professional Treatment: When To Call It In
Home remedies like the five above genuinely have a place, especially as a first response to the odd roach you’ve spotted, or as an extra layer of prevention alongside good sanitation. They’re cheap, low-risk (aside from moth balls, which need careful handling), and easy to try tonight.
Where they run out of road is once roaches are already established. If you’re seeing roaches during the day, finding egg cases (oothecae) or shed skins, or noticing a smell that lingers even after cleaning, that usually points to an active colony living somewhere repellents can’t reach, inside wall cavities, under appliances, or in roof voids.
📞 When It’s Time To Call In A Specialist
- You’ve tried moth balls, cedar, pepper spray, mint oil or bay leaves and the roaches keep coming back to the same spot.
- You’re seeing roaches during the day, not just at night.
- You’ve found egg cases or shed skins in cupboards, behind appliances, or in the roof void.
- The smell of roaches lingers even straight after a thorough clean.
Related → Tips To Eradicate Cockroaches | DIY vs Professional Treatments
What Your Roach Sightings Are Telling You
Good sign: Haven’t seen a roach since placing repellents or cleaning up. Keep monitoring and maintain good sanitation.
Worth watching: One or two now and then, near the same spot. Could just be strays coming in from outside, keep an eye on it and reinforce that entry point.
Likely a bigger problem: Seeing more roaches, in more rooms, or during the day. This points to an established colony that repellents alone won’t fix.
Not sure which category you’re in? A quick inspection can tell you before you commit to any ongoing treatment.
Important: Whatever repellents you try, keep them out of reach of children and pets, and always follow the product label. This applies especially to moth balls, which are a registered pesticide, not designed for open household use.
Frequently Asked Questions
Do moth balls kill cockroaches, or just repel them?
They repel, mostly by smell. They don’t kill roaches or their eggs, and roaches will often simply move to a nearby spot without the smell. See → Pest Control Advice: How To Kill Cockroaches
Are moth balls safe to use for roaches at home?
Only when used exactly as the product label describes, in enclosed spaces, away from food areas, kids and pets. Using them out in the open isn’t what they’re designed for and can create health risks.
Does naphthalene actually prevent cockroaches?
It can make cockroaches avoid a specific enclosed spot while the smell lasts, but it doesn’t address an existing infestation or stop new roaches finding another way in.
Does cedar repel cockroaches?
Yes, to some degree. Testing shows cedar does repel German and brown-banded cockroaches, though it works best in small, enclosed spaces like drawers and closets rather than open rooms.
Do roaches hate pepper?
Roaches tend to avoid strongly scented, irritating substances like red pepper, which is why a diluted hot sauce spray can discourage them from treated surfaces.
How long do natural repellents like these last?
Their scent fades as the oils evaporate or surfaces get cleaned, so most need reapplying every week or two to stay effective.
Why do I still have roaches after using moth balls, cedar or pepper spray?
Repellents move roaches away from a treated spot, they don’t remove an existing colony. If the roaches have another way in or another place to nest, they’ll simply relocate. See → Tips To Eradicate Cockroaches
What’s the difference between a roach repellent and a roach killer?
A repellent changes roach behaviour with scent. A killer, like boric acid, dusts, or professional baits, actually ends their life cycle. See → Get Rid Of Cockroaches, 10 Useful Tips
Reviewed by Robert Luckens, founder of Rockypest, who has worked in pest control since 1988.
Roaches Not Backing Down?
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