Cockroaches are immune to bug spray! | campus.sg

What do you do when you see a cockroach in the house? You either scream and run, grab a bug spray, or possibly have your friends come around and do this:

People always joke around that when the end of the world comes, only the cockroaches will survive. And now there’s evidence to support this claim (sorry, everyone!).

A new study published in Scientific Reports has found that German cockroaches (Blattella germanica) – the ones which are commonly found here in Singapore – are rapidly evolving to become resistant to bug sprays, as well as chemicals they’ve never been directly exposed to. Scarier still is that they could develop resistance within a single generation!

The creepy bugs can also develop cross-resistance to a usually toxic substances simply by being in contact with a similar type of insecticide.  

The researchers used three insecticides – abamectin, boric acid, and thiamethoxam – and found that no matter what the combination, a considerable share of the cockroaches and their offspring had become “essentially immune” to a particular class of pesticide. In short, no matter what bug sprays you use, you’ll never reduce their population. In fact, cockroach populations will actually increase.

Roach Facts to Creep You Out

Roaches can pump out up to 50 offspring during their three-month reproductive cycle, and even if only a small portion develop resistance, they will reproduce and bounce back within a couple of months. 

Roaches carry dozens of nasty pathogens, including E. coli and salmonella, as well as asthma-triggering allergens.

The most annoying fact is that they live exclusively in human environments (German cockroaches, in particular, love paper/cardboard), so they run the risk of being a vector for disease.

So what do you do to get rid of cockroaches? A good stomp with your foot (or a whack with a rolled-up magazine). Of course, the best course of action is a combination of improved sanitation (vacuum and tidy up often), coupled with the occasional bug spray and roach motel traps.