How fungus could help us win the war on bed bugs

Cities across North America and Europe are in the midst of a bed bug epidemic, a plague of bloodsucking parasites that are infesting bedrooms and hotel rooms across the nations. And they are so gross, leaving unwary victims with irritated skin and a profound case of the willies. It's gotten so bad that the U.S. alone spends $250 million each year to fight the bugs, and with little progress. Part of the problem is the understandable reluctance to use chemical pesticides in our sleeping quarters — a dilemma that could be solved by using a natural alternative: fungus.

According to a new study published in the Journal of Invertebrate Pathology, a natural fungus called Beauveria bassiana is being seriously considered in the war on bed bugs. B. bassiana causes disease in insects, including bed bugs. And it's relatively easy to produce in the lab, making them a viable alternative to chemical pesticides.

How fungus could help us win the war on bed bugsS

During the study, which was conducted by entomologist Nina Jenkins, an airbrush sprayer was used to apply the fungal spores to paper and cotton jersey (what are common bed sheet materials). A control surface was also used in which a basic oil was applied.

After drying, three groups of 10 bed bugs were then exposed to one of the two surfaces for an hour. Following the exposure, the bugs were placed on clean filter paper in a petri dish along with unexposed bed bugs. Over the course of the next five days, all bed bugs exposed to the fungal spores had died. And encouragingly, the researchers noted no prominent differences in susceptibility by feeding status, sex, strain, or life stages.

Moreover, the diseased bed bugs infected their unexposed comrades. And in fact, they observed 100% infection. What this implies is that direct exposure to the fungus is not required — what will certainly help exterminators given the bed bugs' penchant for occupying hard-to-reach places. As the researchers noted, bed bugs can hide behind light switches, power sockets, and in between the cracks of the baseboard beneath carpets.

For the next phase of the project, Jenkins and her colleagues will test exposure times and apply the fungal spray to bed bugs in their natural hiding areas. It's not known, for example, the rate at which the bugs can develop an immunity — if at all.

All this said, while Beauveria bassiana is reported to be non-toxic to humans and other vertebrates, its potential allergenicity has not been widely studied. Early indications, however, suggest that it's safe.

The study will appear online at the Journal of Invertebrate Pathologylater this week.

Top image: Shutterstock/Margaret M Stewart. Inset image: Nina Jenkins, Penn State.