Infestation: Biopesticide Shows Promise for Bed Bug Sufferers

Discarded mattress. By Jamie Drummond. CC BY-NC-ND 2.0.

I wanted the journalism experience. That’s why I took an unpaid internship in Washington, D.C., before my senior year of college. As an added bonus that summer, I picked up a case of head-to-toe “bird lice” from the well-traveled futon in the apartment I was subletting. (Not sure where the bird ever was.) Ever since, I have suffered a mild case of what I’ll call FTTCM—fear of tiny things crawling on me. Considering my personal history, it may not have been the best idea for me to get in touch with bedbug expert Nina Jenkins last month. But for the sake of science, I had to give her a call.

Jenkins, senior research associate in entomology, and her colleagues at Pennsylvania State University (Alexis Barbarin, formerly a postgraduate student and now a post-doc at the University of Pennsylvania, and entomology professors Edwin Rajotte and Matthew Thomas), have found a natural fungal biopesticide to deal with these pests. The results of their study on the effectiveness of Beauveria bassiana appear in the Journal of Invertebrate Pathology.

Because of bed bugs’ growing resistance to chemical pesticides, it has become very difficult to get rid of them, Jenkins tells me. “They’ve become a huge problem in city areas: Philadelphia, New York City, and Cincinnati are all in the news for having a high prevalence of bed bugs in hotels and private housing.” (Gulp. I lived in Philadelphia not too long ago. And so did my bed.)

The bites of bloodthirsty bed bugs itch like mosquito bites do. And though there is no evidence that these bugs transmit diseases, they are very inconvenient to have around. “I think a lot of psychological damage goes with that,” Jenkins says. (Not that I would know anything about this.)

“The key to really addressing a bed bug infestation is getting to the harborage (where they bed down), which is otherwise inaccessible to chemicals,” Jenkins explains. “There are so many little cracks and crevices where the populations can hide out. Unless you can physically get them with a chemical, they remain unaffected.”

But bed bugs walk on bent tarsi (tiny “hooks” that make it easy for them to climb up soft furniture and frolic on your futon), so very little of their body makes contact with a surface that’s been sprayed with traditional pesticides. What this means is that little pesticide residue makes it back to the harborage.

The Penn State researchers conducted their tests using an oil spray containing B. bassiana on paper and on cloth. Though the spray is invisible when dry, it distributes enough fungal spores throughout the treated material to make it highly effective against bed bugs.

Once these spores come into contact with the cuticle of the bed bug, they germinate and bore through the epidermis, gradually reaching the hemocoel (body cavity containing the digestive and blood centers), where they do their damage. In the meantime, the insects carry the spores back to their nesting sites, infecting others.

In the Penn State experiment, three groups of ten bed bugs were placed on one of the two treated surfaces or on an untreated (control) surface for one hour. All of the exposed bed bugs died within five days. (As little as a minute of exposure appears to be fatal to the bed bugs, Jenkins says.)

Since their data has been released, Jenkins says they’ve been inundated with calls from long-term care facilities and home-renters who are desperate for a natural and effective way to control bed bugs. (They’ll have to wait while Jenkins and her colleagues do more tests and look for the best ways to bring the fungicide to the marketplace.)

Don’t expect treated sheets, however. Instead, Jenkins expects that a commercially available spray would go around light switches and on baseboards and bedskirts. “This will form a barrier over which bed bugs will have to crawl to find a blood meal.”

Trying to control my own urge to itch, I ask Jenkins if the work ever bugs her. She admits that she does get that skin-crawling feeling at times when she’s working in the lab. That’s because mixed bed-bug populations are hard to spot and keep track of: The adults resemble flattened apple pits, whereas the youngest “first instar” bed bugs are “tiny little dots.”

“Our best joke,” she says, is to announce, “‘Three or four of them escaped! And we’re not sure where they are!’ Everyone freaks out.” I know how they feel.

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4 thoughts on “Infestation: Biopesticide Shows Promise for Bed Bug Sufferers

  1. I travel quite a lot, and am a bed bug magnet. Mosquitos and other nibblers aren’t much of a problem (well except the two times I’ve contracted Dengue Fever), but bed bugs are bad news for me. I’ve picked them up all over the world, literally. What I liked about your post was: “Once these spores come into contact with the cuticle of the bed bug, they germinate and bore through the epidermis…” I am pleased that progress is being made and that the little buggers can be made to suffer as well. Informative post. Thanks. James

    • Thanks for visiting my blog, James. Yes, I’m glad there are some positive developments in this field. Happy travels, and don’t (or try not to) let the bed bugs bite! Susan

  2. Interesting–and hopeful–news! Just thinking about bed bugs makes my skin crawl. A friend of mine had an awful time getting rid of them in her house. And my mom’s apartment house–in Philadelphia–had some problems with bed bugs, too. Luckily not in her apartment though.

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