SAN FRANCISCO (KRON) – Next time you try to squash a cockroach or spray it to death with a repellent of sorts, you may have to try a little harder than that!

That’s because cockroaches are getting a lot tougher and are developing cross-resistance to a number of insecticides, according to a new study published in the Scientific Reports journal.

The study found that German cockroaches, which are the most common species of insect in the world, are stepping up their defenses against poisons designed to kill them.

Researchers tested different insecticides from different classes in Indiana and Illinois over a 6-month period, mixing insecticides to make sure they’re eliminating bugs that have developed a resistance to one.

Scientists were apparently able to keep cockroach populations at bay through rotating insecticides, but were not actually able to reduce their numbers.

The super-immune insects can then pass their resistance on to their offspring, making it only a matter of time before a given population becomes, essentially, insecticide-proof.

“This is a previously unrealized challenge in cockroaches,” says Michael Scharf of Purdue University, who led the study. “Cockroaches developing resistance to multiple classes of insecticides at once will make controlling these pests almost impossible with chemicals alone.”

Scharf says resistance within a single generation of the cockroaches sometimes increased four- or six-fold.

Combine that with the fact a single female cockroach can produce 200 to 300 offspring in her short lifetime and, well, you’re looking at some cursed math.

Scharf’s team concluded the issue is worse in low-income areas and other places where effective pest control isn’t available.

The way to combat this, Scharf says, is to diversify pest treatment methods. This could include physical methods like traps and vacuums, and preventative measures like sanitation.

After all, cockroaches were on this earth millions of years before us. As they evolve, so must we; or they’ll be here millions of years after we’re gone.

CNN contributed to this reported.