Swarms of mosquitoes are annoying enough, but now the world has the terrifying Zika virus to contend with. What to do about those annoying suckers? The solution might be as close at hand as your cup of coffee. Research suggests that mosquitoes hate the smell of coffee (which seems weird but hey, more for us!).
Last year, The Huffington Post reported that coffee had been used to kill the larvae—baby mosquitos—of a breed of mosquito related to the one that causes Yellow Fever. And a U.S. National Library of Medicine study showed that female mosquitos would lay fewer eggs on land that happens to be covered with coffee grounds.
This concept is gathering so much steam that there’s even a YouTube video by Abuela Mami showing how to use Cuban coffee in your own backyard to ward off mosquitos. Bonus? The coffee helps to fertilize your plants while it’s at it.
So how much of the coffee theory is wishful thinking?
“In general it is known that mosquitoes are attracted to odors — for example certain human odors are attractive to mosquitoes," Amesh A. Adalja, a board certified infectious disease physician at the University of Pittsburgh, told The Feast. "The use of coffee against mosquitoes has involved demonstrating that coffee can kill the larvae of certain mosquitoes if placed in the standing water in which they breed. There is also evidence that the presence of coffee is a repulsive towards female egg-laying mosquitoes. As insecticide resistance increases, it will be important to develop new measures to control mosquito populations and coffee-based solutions may have some promise."
For now, it's important to be cautious while those (delicious-smelling?) solutions are still being developed. “There is no scientific proof that coffee can prevent mosquito bites. People who have tried this may have found that spreading coffee grounds may decrease the amount of mosquitos around you, and argue that the smell acts as a repellent. However, there is no real scientific evidence to suggest this,” Dr. Lisa Ashe, Medical Director, Be Well Medical Group, tells The Feast.
“Since this is not your typical mosquito outbreak, when warding off mosquitos, I do recommend that you choose a repellent that is registered by the EPA and listed on the CDC website, such as citronella and eucalyptus. If you’re not sure if your current repellent is registered, simply visit the EPA website and type in the ingredient,” Ashe adds.
You won't find coffee in that EPA search engine (we tried), so you won't want to go traipsing off in mosquito-heavy areas wearing only eau de coffee on your body. But the U.S. National Library of Medicine's findings are nonetheless encouraging:
"There are many reasons for optimism that coffee may be useful in mosquito control. Some Coffea plants are naturally resistant to insect attack. Roasting coffee beans produces compounds mutagenic to bacteria. Coffee has antibacterial and antiviral properties. Caffeine impedes the web-building activity of spiders, kills certain insects, and inhibits feeding in flies and beetles. Coffee also decreases the reproductive capacity of mosquitoes...., " the Library states on its website.
Barring the option of turning every puddle of mosquito-breeding stagnant water on Earth into a giant vat of coffee, there's one small thing we can do at home in the meantime, as the Huffington Post report suggests: Save our otherwise wasted, used coffee grounds and sprinkle them around the garden or outdoor areas.
If you're like us, that's a lot of coffee grounds. Worth a shot, no?
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