Cockroach killers review

Test results for three types of cockroach control

Find out which type of cockroach you need to get rid of, then look for the best-performing product on test

The main types of cockroach we see being either the larger American or smaller German cockroach. American cockroaches are found inside and outside the home, while the German species mainly lives inside. Both are a nuisance, and left unchecked can reach infestations of epic proportions.

Unfortunately, it’s unlikely you’ll ever be completely rid of cockroaches in your home, but there are ways you can control them.

CHOICE tested three types of chemical control:

• knockdown sprays for individual cockroaches
• surface sprays
• baits and traps for more preventative, long-term control

Some surface sprays claim to last more than three months; we’ve tested their effectiveness over a one-month period and have also reported on their three-month performance.

Invulnerable cockroaches?

When we tested cockroach killers in 1999 and 2004 we found that the same active ingredients (second and third-generation pyrethroid insecticides) that were tested in 1999 were less effective in the 2004 test at the three-month mark. We will be revisiting the current crop of surface sprays at the three month mark to see whether this pattern is repeated.

Why do active ingredients lose their long-term effectiveness?

According to our expert lab, a likely explanation is that the cockroaches have developed resistance to the older second and third-generation pyrethroid insecticides.

The development of insecticide resistance in the German species is well documented. In fact, chlordane-resistant German roaches were identified as far back as the early 1950s, and resistance to all major groups of insecticides has now been reported in various roach populations around the world.

Other insects, such as malaria-carrying mosquitos, have also developed resistance to various insecticides. And they’re not the only examples of resistant bugs posing a threat to humans or valuable crops.

Experts caution that the responsible use of insecticides is an important factor in controlling the development of insecticide resistance. For cockroaches, this means the integrated approach — not overusing insecticides and also taking into account good hygiene and cockroach habits.

Value for money?

Same product, different price tag

The two major supermarkets make much of their own home brands, and in particular their “luxury” home brands such as Woolworths Select and You’ll Love Coles. CHOICE was staggered to discover that two of the products on test, Home Brand Insect Spray Low Irritant and Woolworths Select Low Irritant Insect Spray, have identical active ingredients in identical quantities, but the luxury brand is twice as expensive per 100 grams and comes in a smaller container. To add insult to injury, both also have below-average performance, taking over 10 minutes to kill our samples of the larger American cockroach.

Bigger not always better

Occasionally we see larger one or two litre packs of cockroach killers which often don't come with a propellant but rely on you to pump the product out of the container. The larger pack can give the illusion of getting more for your dollar.

If you’re tempted to try one of these DIY surface spray pack options, such as the Mortein Do-It-Yourself Professional Indoor Surface Spray or Hovex 2 in 1 Outdoor & Indoor Surface Spray; the Mortein is more expensive than the Atlas equal top rating surface spray, and the Hovex 2 in 1 Outdoor & Indoor Surface Spray is less effective than some of the cheaper can options.

Here are a few samples of warnings we found on some cans of cockroach killer:

Keep out of reach of children.
Not to be taken.
Extremely flammable.
Do not spray into air.
Do not spray towards the face.
Do not spray directly onto humans, pets, exposed foods, food utensils or food preparation surfaces.
Remove or cover fish tanks and birds before spraying.
Poison.
Do not apply to food plants.
Do not allow chemical containers or spray to get into drains, sewers, streams or ponds.
Do not spray if bees are foraging on flowering plants.
Dangerous to fish.
Will damage eyes.
Avoid contact with eyes and skin.
Do not inhale vapour.
When using the spray wear cotton overalls buttoned to the neck and wrist, rubber gloves and goggles.
Do not spray on painted surfaces.
Many of the surface sprays warn against using as a space spray, or knockdown spray.

As consumers, some of us tend to be blasé about poison warnings. We grow up being told that we are to pay attention to poison warnings, and now we just avoid ingesting directly. Pets don’t have this education, and babies are only just in the process of learning. If you have either pets or babies, pay particular attention to poison warnings: toxins kill.

Spraying toxic chemicals on floors or any easily accessible surface is an invitation to both children and pets to ingest it. Babies are exceptionally curious and they will try everything, so the best way to avoid poisons is to avoid using toxic chemicals and use preventative measures instead.

If you are not able to utilise preventative measures, then using exclusionary zones can be a useful way around it. Spraying the kitchen floor but having a gate at the entry points to the kitchen can help, but keep in mind when you walk on the floor you will track those chemicals through to other areas of the house.

Areas of infestation are usually away from open areas as cockroaches tend to like closed dark spaces. Targeting the surface spray or bait in areas like cupboards under the sink or behind the fridge where babies and pets are unlikely to get to due to a lock on the cupboard and the fridge being inaccessible helps avoid unfortunate accidents. Check out our Prevention page for other ideas.

Preventative measures

The best way to solve your cockroach problem is to make your home as unwelcoming for them as possible.

• Turn off your appliances to limit the warm, dark places cockroaches can hide, such as kettles, microwaves, etc.
• Thoroughly clean your home at least weekly, and clean regularly underneath the fridge, stove, toaster and other movable appliances.
• Cockroaches live close to food preparation areas, so keep these areas clean. Wipe up food spills promptly and thoroughly. Pet-food bowls are a perfect source of food for cockroaches, so keep them cleaned and outside.
• Empty the kitchen rubbish bin regularly. Compost bins need secure doors or screens and should be kept away from the house. Make your rubbish hard to reach and keep organic waste in tightly covered garbage cans.
• Keep food in sealed containers.
• Cockroaches love small enclosed spaces, so seal any holes, cracks or gaps in the walls, skirting boards and inside cupboards.
• Newspapers, magazines and cardboard boxes are great homes for cockroaches, so don’t accumulate them in the house.
• Leaving the dishes in the sink overnight creates a feast for cockroaches while you sleep.
• Cockroaches need to drink, so wipe up any spills immediately and don’t let taps drip.

Natural alternatives

There are alternatives to chemical products but they tend to be preventative measures rather than instant solutions. Natural oils, maintaining good storage practices and using fly screens and insect excluders can help make your home a haven, excluding cockroaches and other pests in general. Naturally occurring botanical pesticides such as neem or pyrethrum can also have an impact.

The only “natural” product on test is Hovex Natural Cockroach Traps. The manufacturer, Pascoes, told CHOICE it uses an all-natural food source and glue to trap cockroaches . Unfortunately, both traps and baits are poor performers overall. Check out their individual scores to see which one works for you.