Dealing with ants, cockroaches and flies around house without chemical sprays

By Carol Rääbus, ABC Life

20 March 2019

4 minute read

A fly against a pink window pane

Flyscreens are a much better solution than fly spray to keep blowflies out (ABC Life: Nathan Nankervis / Flickr: Emma Forsberg)

Lots of us get a bit freaked out when we spot critters scuttling across the kitchen floor and, instinctively, we reach for the insecticide spray to kill.

But there are ways we can deal with bugs without resorting to chemicals, and the uncomfortable truth is there are some creepy crawlies we’re better off keeping around.

Tanya Latty, an entomologist at the School of Life and Environmental Sciences at the University of Sydney, wants us to stop and think before we try to slay anything we find in our homes. “I’m not sure where it originates, this idea that your house is supposed to be sterile and your garden should have just flowers and no insects,” Dr Latty says. “It’s not achievable for one thing, but it also sets up this idea that as soon as you see an ant or a cockroach in your kitchen you have to nuke the place.”

Dr Latty and Bryan Lessard, aka Bry The Fly Guy from the CSIRO, share their tips to help you keep bugs at bay.

A picture of a dead cockroach

The cockroaches you find are seldom Australian native cockroaches. They’re most likely to be introduced pests like German cockroaches or American cockroaches (pictured).

Bug are gross … or are they?

Are cockroaches, ants and flies wandering about your home actually dangerous to our health? Not really, says Dr Latty and Dr Lessard.

“The main risk for things like cockroaches is the fact that bacteria can stick to their feet, so if a cockroach runs across some raw chicken on the bench and then runs across your salad, then it can move the bacteria from the chicken to the salad,” she says.

Some people can be allergic to cockroach exoskeletons and their poop, but that will only be a problem if you have large numbers of them. “Having huge numbers of cockroaches in your kitchen is probably not great,” Dr Latty says. “But having one cockroach doesn’t mean you’re going to die of the plague. You get way more [bacteria or pathogens] from another mammal than any insect.”

Dr Lessard says apart from mosquitoes, which are a type of fly, even the biggest blowfly isn’t very likely to bring you any harm.

Ants also tend to not be a real health risk, unless you’re unlucky enough to have a fire ant nest invading your dining space. The little black house ant, sometimes called sugar ants, aren’t dangerous.

Dr Latty says our sense of risk with insects, even when it comes to venomous spiders, tends to be “totally warped”. “You’re literally more likely to be hit by lightning than to die of a spider bite,” she says.

A picture of a huntsman spider on a fridge

Huntsman spiders are your friends. These Australian spiders eat cockroaches, flies, ants and other spiders, so it’s a good thing to have them around.

Why are there insects in my house?

It’s not just cockroaches, ants and flies hanging out in your pad, you’ve probably got about 100 different species of insects living with you, most of which you don’t even notice. Bugs move in with us for the food, water and warmth our homes provide. So if you’re trying to evict unwanted roomies, you need to stop them having access to the things they want.

Dr Latty and Dr Lessard say preventing unwanted insects from getting inside in the first place is better than launching chemical warfare.

Excerpt published with permission from ABC Life.