Got a cockroach problem? Total release foggers are not the solution, warns a study from North Carolina State University, published in BMC Public Health. Also called “bug bombs,” these products send aerosolized particles of insecticide throughout a room.
To see how foggers measure up in effectiveness and safety, researchers treated the kitchens of 20 homes with evidence of roaches with one of four commercial products (all containing pyrethroid insecticides), following manufacturers’ instructions and EPA precautions. They treated another 10 homes with gel baits (active ingredient fipronil), dabs of which are applied into cracks and crevices where roaches travel or areas where they hide.
Compared to baseline, only the baits resulted in significant roach reduction. Moreover, after fogger treatment, insecticide residues were found on most kitchen surfaces and all horizontal surfaces, with residues remaining high on 34 percent of the horizontal surfaces after one month, and moderately high on half of them. In contrast, the baits left no detectable residues (the chemicals are not volatile).
The toxic substances in foggers present acute and possible chronic health risks and have been linked to respiratory, gastrointestinal, neurological, dermatological, and other adverse symptoms. The aerosolized particles are also highly flammable and can set off explosions—for instance, if pilot lights or gas fireplaces are on or if certain appliances are not unplugged.
The foggers may be ineffective because the roaches move to areas where the insecticide particles can’t reach (such as the underside of shelves and under the kitchen sink), plus the insects have developed resistance to the pyrethroid chemicals (including permethrin) used in them. Commercial insect sprays are not the solution, either, since they typically contain the same pesticides that roaches are resistant to, and they also leave behind extensive pesticide residues. The gel baits work because they attract the roaches, which then carry the insecticide to places where aerosol foggers can’t reach.
The researchers concluded that the “proper use of baits constitutes the most cost-effective intervention to mitigate the harmful effects of cockroaches and their allergens.” Still, the baits did not kill all the roaches in the study because more time may be needed for that, plus other anti-roach tactics (like caulking) may be needed to banish them completely. For serious problems, get advice from a pest control service. Some companies use “integrated pest management,” which minimizes the need for pesticides and other toxic chemicals.
This article first appeared in the UC Berkeley Wellness Letter.
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