Laurence Dollimore
COCKROACHES have begun developing a cross-resistance to powerful insecticides, an alarming new study has found.
Scientists from Purdue University exposed German cockroaches to different insecticides, and found that the populations not only developed a resistance to the insecticide they were exposed to, but also picked up resistances to other insecticides.
The vile bugs, which come out in force across Spain in the warmer months, can actually pass their resistance on to their offspring, the study concluded.
This means it is only a matter of time before populations become practically insecticide-proof.
“This is a previously unrealised challenge in cockroaches,” said Michael Scharf of Purdue University, in the US, who led the study.
“Cockroaches developing resistance to multiple classes of insecticides at once will make controlling these pests almost impossible with chemicals alone.”
The research was published in the journal Scientific Reports.
German cockroaches are the most common breed in Spain.
A cocktail of different insecticides are usually used to wipe out the vermin, and are divided into classes based on toxicity, chemical composition and other factors.
Usually, if an insect is immune to one kind, another kind can knock them out.
But this doesn’t work if cockroaches become immune to different types.
In the study, cockroach populations were kept level by switching out insecticides, however scientists weren’t actually able to reduce their numbers.
Scharf told CNN that resistance within a single generation of the cockroaches sometimes increased four- or six-fold.
The issue is reportedly worse in low-income areas and other places where effective pest control isn’t available.
The way to combat this, according to Scharf, is to diversify pest treatment methods.
