Insecticides are ineffective for eradicating cockroaches in commercial settings.

People buying insecticide sprays to get rid of cockroaches are wasting money because the bugs have developed a resistance to the key ingredients, prompting calls for U.S. regulators to tighten product testing rules.

There are about 30 species of cockroaches living around humans, but the German cockroach (German cockroachThe common dust mite ( ), found worldwide, is the dust mite most likely to infest buildings. Previous research There is evidence of widespread resistance to pyrethroid insecticides, which are commonly found in consumer products.

now, Jonalyn Gordon University of Florida researchers found that while commercial insecticides continue to work effectively on lab-derived German cockroaches bred from strains that have not been exposed to insecticides, they are ineffective against insects taken from real-world infestations.

The products are designed to be sprayed on surfaces to kill insects that walk across them, but in the team's tests, the coated surfaces killed fewer than 20 percent of the cockroaches they collected after 20 minutes of exposure. “Spraying these products directly in a closed container did not result in a 100 percent kill rate,” Gordon says.

When cockroaches were forced to remain on treated surfaces, most products took between eight and 24 hours to kill them. Previous research In reality, this is unlikely to occur, as these insects have been shown to avoid landing on pyrethroid-treated surfaces.

Pest-control products sold in the United States are regulated by the Environmental Protection Agency and manufacturers must prove they are 90 percent effective, but field testing on insects is not generally required.

That needs to change, Gordon says, noting that any bedbug-control products sold in the US should be required to be tested on recently collected specimens. “If that were to happen for cockroach control, I think it would raise the bar for cockroach-control products and ensure that the products on the shelves are providing the control people reasonably expect,” Gordon says.

In the meantime, cockroach repellents are probably the most effective consumer product for controlling pests, with the added benefit of minimizing human exposure to pesticides, Gordon says. Home measures like eliminating food and water sources the pests use and cleaning up clutter can also help. Professional pest control using non-pyrethroid insecticides is also recommended.