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Kidney-bean leaves may help eradicate bedbugs, study suggests

bean plant
Bean plants may work as bedbug traps, but they’re obviously an impractical solution for widespread and large infestations.

Bedbug infestations have returned with a vengeance over the past decade or so, including here in Minnesota.

Entomologists cite many possible factors behind the resurgence of these tiny, oval-shaped, blood-sucking insects, including the creatures’ increasing biological resistance to pesticides, the rise in international travel and years of public complacency.

Bedbugs, which like to hang out in beds and other warm, dark places that humans frequent, aren’t a serious health hazard. They don’t cause illness, except in very rare cases when someone is allergic to them. Still, the bites can itch and lead to a mild skin rash.

And then, of course, there’s the eew factor — the knowledge that something is biting and consuming your blood while you sleep (or while you try to sleep).

So a study published earlier this month that details how scientists at the University of California, Irvine, and the University of Kentucky are pursuing a promising bedbug solution based on a simple southeastern European folk remedy caught many people’s attention.

The remedy is the common kidney-bean leaf, which in times past people in some areas of the Balkan Peninsula would apparently scatter on the floor around their beds at night. In the morning, dozens of bedbugs would be trapped on the leaves — their feet caught and pierced by the leaves’ tiny hooked hairs, called trichomes. The leaves would then be removed from the house and burned.

Bean plants may work as bedbug traps, but they’re obviously an impractical solution for widespread and large infestations. For one thing, the leaves only work when freshly picked. The authors of the new study are therefore pursuing synthetic materials that might mimic the leaves’ penetrating hairs — materials that could then be used to create an artificial trap. So far, such a device has eluded the scientists, but they believe they’ll be successful at constructing one soon.

Not the only folk remedy

Kells portrait
Stephen Kells

“I think it’s a good start and an interesting and novel idea,” said Stephen Kells, a University of Minnesota entomologist and bedbug expert, in a phone interview last week. He’s not sure, however, how practical the device will be.

“To be useful it would have to be able to collect a lot of bedbugs,” he said.

Kells had not heard of the Balkan bean-leaf remedy until he read the new study, but he said people have tried many other non-toxic ways of getting rid of bedbugs down through the centuries. “On ships back in the 1800s, they’d paint over any bugs and encase them in white wash or lime material,” he said.

Another common folk solution was to trap the insects in a moat of hot water formed on the floor around the infested bed.

The modern version of these hot-water traps is, of course, washing all bed linen in hot water and then drying the linen at a high heat. Bed bugs are, however, notoriously difficult to get rid of, so to ensure an infestation is truly gone, the best thing to do is to call a pest-control company, said Kells.

If you don’t want to go the insecticide route, the experts can provide another option: controlled heat. “They’ll heat up the living area to 122 degrees, and that will get rid of the bed bugs,” said Kells.

Don’t try that solution on your own, however. “It requires special equipment,” stressed Kells. “People have started fires trying to do it themselves with inappropriate materials.”

Resurgence hit Minnesota early

Minnesotans should not feel smug about being left off the “top 10” lists of metropolitan areas with the worst bedbug infestations. Minnesota is actually badly infested, said Kells, and was one of the first states to encounter the latest bedbug resurgence.

The reason we don’t make those top 10 lists, he explained, is because the pest-control companies that compile the lists do so for marketing purposes. “Proportionally, they have less of a market share in Minnesota than they do in other places, so they under-represent this area,” he said.

Kells also cleared up another misunderstanding about bedbugs: that only lower-income people who are poor housekeepers need to worry about their homes becoming infested.

“That’s not true,” he said. “Bedbugs like warm bodies. They don’t look for people who are messy or anything like that.”

“Families who are financially strapped may not be able to devote the attention and resources to controlling [the bedbugs] as people in higher incomes do,” he added. “But people in mid and high incomes get bedbugs, too.”

A great local resource

The University of Minnesota has a terrific website devoted to these ubiquitous insects. It will tell you how to recognize them and what to do — and not to do — to get rid of them.

The site also lists tips for keeping the insects out of your home in the first place. (Here’s one you may not have thought of: When you return home, don’t place your backpack, purse or bag on beds, couches, or other areas where you rest.)

You can also try growing kidney beans this summer.

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