First the ability to survive nuclear apocalypses, now pesticides…
A new study has found that German cockroaches (Blattella germanica) are rapidly evolving to become resistant to many widely used bug sprays and insecticides, as well as chemicals they’ve never been directly exposed to, making them nearly impossible to eliminate.
It’s been revealed that the bugs can seemingly develop a resistance within just one generation, even to pesticides they’ve not been directly exposed to, but by being exposed to a similar chemical.
“We didn’t have a clue that something like that could happen this fast,” lead author Michael Scharf, of the Department of Entomology at Purdue University, said in a statement.
“We would see resistance increase four- or six-fold in just one generation.”
The researchers tested out different treatments of three commonly used pesticides; abamectin, boric acid, and thiamethoxam, in numerous cockroach-infested apartments across Indiana and Illinois over the course of six months. In one treatment, three different insecticides were rotated each month for three months and then repeated. In a second, they used two insecticides from different classes for six months. In the third, they chose one insecticide to which cockroaches had low-level starting resistance.
Despite the use of multiple different chemicals, the researchers were unable to reduce the size of the cockroach population. In the single insecticide treatment, populations grew with around 10 percent as individual roaches starting to evolve resistance. Even with the two insecticide treatments, the cockroach population didn’t decline, but it instead skyrocketed.
Cockroaches aren’t just annoying pests, they also carry dangerous diseases like E Coli, which is why it’s such a concern that they can’t be easily eradicated by pesticides. Researchers are trying to understand why this rapid resistance happens, and how to combat it.
“This is a previously unrealised challenge in cockroaches,” concluded Scharf. “Cockroaches developing resistance to multiple classes of insecticides at once will make controlling these pests almost impossible with chemicals alone.”
