This is probably more information than you want to know about cockroaches. There are over 400 different species of cockroach in Australia but there are really only 5 which are considered pests.
Big Black & Brown cockroaches
By big I mean cockroaches that grow to 3 or 4 centimetres in length. There are a couple of varieties but when they scurry around, they pretty much all look and act the same. These large cockroaches prefer the outdoors and will travel reasonable distances looking for food, shelter and ‘friends’. They eat organic material and are more at home in leaf litter and rotting wood than they are in a pantry, that is unless they find spilt food or containers that aren’t sealed shut properly.
When you turn on a light late at night and see them scurrying across floors, benches etc they are trying to find a place to hide. If it’s a bathroom, they will run down a floor waste to hide. People mistake this as proof they live in property’s floor drains. They do not. Our floor drains in bathrooms and laundries have water barriers to stop smells coming up from the sewer. Cockroaches are a lot of things, but they are not scuba divers. Most get into your property through gaps in windows and floors. They wander around looking for food and if they don’t find any they leave again.
We tend not to use pest sprays for these guys. They are never in numbers large enough to justify spraying and cockroach baits usually work better.
Smaller dark brown cockroaches
These are much smaller coming in at around 1-1.5 centimetres. And when they infest a property, they really take over. The most common are German cockroaches, though people refer to them by other names as well. They love warm, moist areas in kitchens, particularly around water heaters and the back of fridges. And because they like the heat, they tend to work their way in amongst the electrical circuits in appliances. Not being too bright, they often electrocute themselves and in so doing they can often short out the appliance and damage it. A lot of manufactures for dishwashers and water heaters specifically exclude repairs under warranty if cockroaches are involved.
Where the big ones are at home outside, these small ones are mainly in buildings. They are brought into property by people bringing in cardboard boxes that have cockroach eggs hiding in the corrugations. They also don’t go wandering. For these reasons NCAT applies the 3-month rule. If a property has these cockroaches in the first three months of a tenancy, it is assumed the cockroaches were there before the tenancy, and it is the owner’s responsibility to treat them. If the cockroaches are reported after the first three months, then it is more than likely that the tenant brought them in, and they are responsible for the cost of treatment.
Just like the big cockroaches, these little ones are attracted by food, and it doesn’t have to be much. Benches not wiped over, spills left on a stove top, or cupboards not properly cleaned. They love water heaters because of the heat. They were originally from Southeast Asia and have travelled the world courtesy of us humans transporting their eggs.
Treatment
Pest spraying is usually focused on areas where they hide or close by to those spots. Spray treatments aren’t barriers that immediately kill all cockroaches. To do that would require a level of toxicity that isn’t safe for us humans. Instead, the sprays work by making them sick and in time, dying. That reduces the population, and the breeding numbers over time until the population collapses.
So long story short, the big cockroaches will always be around. They don’t cause issues and apart from cockroach baits, we tend to leave them alone.
In the case of German cockroaches, we want to know about them, so they don’t damage the appliances in the property. These cockroaches can’t be treated by baits but need to be sprayed. If you don’t report them as required by the lease and they damage an appliance, the cost of that damage can be back on you.
Anyway, like I said, probably more than you wanted to know.
Author – Stephen Jackson.
