Jeffrey Hahn, Asst. Extension Entomologist
The resurgence of bed bugs in the U.S. over the last 10 or so years has increased many people's awareness of these biting insects. They have presented residents and pest management professionals a tremendous challenge to detect and eliminate them. A popular tactic used by residents in bed bug control is the application of total release foggers, also known as bug bombs. Many people have turned to these products to help them control their bed bug problems. But are they effective? This question was examined in a research study conducted by Drs. Susan Jones and Joshua Bryant at Ohio State University.
Photo 1: Bug bombs are not effective in controlling bed bugs. One reason is the insecticide does not reach where the bed bugs hide.
They compared three popular bug bombs that are available to residents. The Hot Shot Bedbug and Flea Fogger is specifically labeled for control of bed bugs and was more extensively tested. They also examined the Spectracide Bug Stop Indoor Fogger and Eliminator Indoor Fogger. Although these products are not listed specifically for bed bugs, they are labeled for flying and crawling insects and could be used by Minnesotans in an attempt to eliminate bed bugs.
Jones and Bryant tested these products against five different populations of bed bugs collected from home infestations in Ohio. They also tested these bug bombs against a strain of bed bugs that has been reared exclusively in a laboratory for 39 years. These bed bugs have never been exposed to pesticides and are susceptible to bed bug products. All of these bed bugs were exposed to the Hot Shot Fogger in three scenarios, direct exposure, optional harborage (they could hide under filter paper), and forced harborage (they were covered by a thin fabric covering). The other two foggers were used only in direct exposure and optional harborage experiments (they were unable to complete the Eliminator Fogger and optional harborage trial) against two of the field collected bed bugs as well as the continuously lab reared bed bugs.
All three bug bombs had generally little effect on the 'wild' collected bed bugs in the direct exposure experiment (with one moderate exception). However, most or all of the lab reared bed bugs were killed. Similar results were seen in the optional harborage experiment except that it took longer to kill most or all of the lab reared bed bugs. In the forced harborage trial, all bed bugs, including the susceptible lab reared bed bugs, were minimally affected by the Hot Shot Fogger.
So what does all of this mean? The short answer is that bug bombs are not effective in controlling bed bugs. There are several reasons why this is true. First, the bed bugs that we battle in our homes are generally not affected by the insecticides contained in bug bombs, even if they are directly exposed to them. There has been growing evidence of varying degrees of bed bug resistance (i.e. they are much less vulnerable) to pyrethroid insecticides which is the primary active ingredient of bug bombs. Only bed bugs that have never been exposed to insecticides could be easily killed and then only if they were directly exposed or were exposed before they sought a place to hide. This research project also concluded that bug bombs were ineffective because of short exposure times, the low concentration of insecticides, and the lack of residual activity.
Bug bombs are also not effective because the insecticide does not penetrate to the harborages where bed bugs hide. This is critically important as these biting insects spend most of their time hiding in cracks, tight spaces, behind and under objects, and similar places (up to 80% of them hide in harborages during the day). They are infrequently out in the open for any length of time and even then just a few at a time. For bug bombs to be effective, they need their target insect to be out in the open long enough for the insecticide to reach them. This research also found that even the susceptible populations of bed bugs were largely unaffected when they were in protected sites.
While bug bombs are not the answer, there are a lot of positive steps you can take to help control a bed bug infestation. See the University of Minnesota's Let's Beat the Bed Bug web page. From there you can access a variety of fact sheets and other sources of information as well how to contact the Bed Bug hotline.
The results of this research were published in the Journal of Economic Entomology, 105(3): 957-963 (2012). A summary of this research was also published in Pest Control Technology in the October 2012 issue.