An old folk remedy involving hairy bean leaves strewn around the bedroom may have a new life as a modern bed bug trap, according to new research from the University of California, Irvine and the University of Kentucky.
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Although its mechanisms weren’t known at the time, the tactic dates back to at least 1678, when the English philosopher John Locke wrote of placing kidney bean leaves under the pillow or around the bed to keep bed bugs from biting as he traveled through Europe.

In the early twentieth century, the approach was also common throughout the Balkans, according to a 1927 report from the Imperial and Royal Austro-Hungarian Army. That report suggested the leaves stunned the bloodsucking bugs as they traveled from hiding places to their sleeping hosts during the night; in the morning, the bug-covered leaves were removed and burned.
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“The inconvenience of bean leaves is that not everyone wants them scattered around their bed room.” Synthetics mimicking the surface of the bean leaf, however, could be placed “as a ring around the bed legs, a floor mat at the door, a strip on the bed board, it could be something one put’s in one’s suitcase,”