(Beyond Pesticides, November 29, 2012) Preliminary research from Penn State finds that a natural fungus, Beauveria bassiana, may be used to control bedbugs. The study, entitled “A preliminary evaluation of the potential of Beauveria bassiana for bed bug control,” finds that all of the bedbugs exposed to the biopesticide became infected and died within five days. The research found no differences in insect’s susceptibility to the fungus due to feeding status, sex, strain, or life stage. Most importantly, the infected bedbugs carried the biopesticide back to their hiding places, infecting those that did not go out in search of blood.
“We exposed half of a population of bedbugs to a spray residue for one hour and then allowed them to go into a harborage with unexposed individuals,” said Nina Jenkins, senior research associate in entomology. “The fungal spores were transferred from the exposed bug to their unexposed companions, and we observed almost a hundred percent infection. So they don’t even need to be directly exposed, and that’s something chemicals cannot do.”
This result is important because bedbugs live in hard-to-reach places. “Bedbugs tend to be cryptic, and they’ll hide in the tiniest crevices,” said Ms. Jenkins. “They don’t just live in your bed. They hide behind light switches and power sockets and in between the cracks of the baseboard and underneath your carpet.”
Ms. Jenkins, working with Alexis Barbarin, Ph.D., a former Penn State postgraduate student now at the University of Pennsylvania, Edwin Rajotte, Ph.D., professor of entomology, and Matthew Thomas, Ph.D., professor of entomology, looked at how B. bassiana acts through contact with its insect host. The researchers used an airbrush sprayer to apply spore formulations to paper and cotton jersey, a common bed sheet material. Then control surfaces, again paper and cotton jersey, were sprayed with blank oil only. The surfaces were allowed to dry at room temperature overnight. Three groups of 10 bedbugs were then exposed to one of the two surfaces for one hour. Afterward, they were placed on clean filter paper in a petri dish and monitored. The research is published in the Journal of Invertebrate Pathology.
“They are natural diseases that exist in the environment,” Ms. Jenkins said. “They are relatively easy to produce in a lab and stable, so you can use them much like chemical pesticides.”
Beyond Pesticides has long been an advocate for the use of non-toxic and least-toxic pesticide alternatives; however, while biopesticides are traditionally classified as a least-toxic method for pest management, products that are designed to kill living organisms should always be treated with caution. In order to successfully deal with any pest infestation, one must embrace an organic, or integrative pest management (IPM) approach which is a program of prevention, monitoring and control, using least-toxic pesticide products, including biological controls, only as a last resort. Methods such as vacuuming, steaming, and exposing the bugs to high heat can control an infestation without dangerous or unwanted side effects. This approach, as well as taking steps such as sealing cracks and crevices, reducing clutter and encasing mattresses, can also help to prevent an infestation in the first place.
This is not the first time a fungus has proven to be an effective natural pesticide. The fungus B. bassiana is also known to be an effective biological control for many other household pests, including termites, aphids, and chinch bugs. The naturally occurring fungus Metarhizium anisopliae has shown promise in reducing blacklegged, or “deer” ticks, and is effective at controlling a wide range of crop pests. In 2009, an Australian government study has shown that lice on sheep may be controlled by fungal biopesticides. Researchers at Utah State University are studying a fungus that kills Mormon crickets (Anabrus simplex) by depositing spores inside them that multiply and eventually break through their exoskeletons.
For more information on how to prevent and manage bedbugs, see Beyond Pesticides’ Bedbugs program page.
Source: Penn State Press Release
All unattributed positions and opinions in this piece are those of Beyond Pesticides.