Using bean leaves to fight bedbugs
Generations of Eastern European housewives doing battle against bedbugs spread bean leaves around the floor of an infested room at night. In the morning, the leaves would be covered with bedbugs that had somehow been trapped there. The leaves, and the pests, were collected and burned — by the pound, in extreme infestations.
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But even though there is no indication that the bean leaves and the bedbugs evolved to work together, the leaves are fiendishly clever in exploiting the insects’ anatomy. Like the armor covering knights in medieval times, the bedbug’s exoskeleton has thinner areas where its legs flex and its tiny claws protrude — like the spot where a greave, or piece of leg armor, ends.
“The areas where they appear to be pierceable,” Dr. Loudon said, “are not the legs themselves. It’s where they bend, where it’s thin. That’s where they get pierced.”
This folk remedy from the Balkans was never entirely forgotten. A German entomologist wrote about it in 1927, a scientist at the United States Department of Agriculture mentioned it in a paper in 1943, and it can be found in Web searches about bedbugs and bean plants.
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