by Kevin Burton
I am late to the great caffeine-vs-decaf debate. But if we take caffeine from our coffee, let’s certainly not throw it out altogether.
Why not? Because caffeine is a natural insecticide, according to the New York Times and others.
Yesterday I mentioned that I am considering switching to decaf coffee and have sort of started down that road, mixing in at least one cup of decaf daily.
But as for caffeine killing bugs, I’ll drink to that, caffeine or not!
“Caffeine and related compounds are potent, natural insecticides that help plants ward off damaging pests, a Boston researcher has found. The findings could lead to a new way to fight insects,” the Times wrote.
“In a report published in the journal Science, Dr. James A. Nathanson said the natural function of caffeine in plants has been a mystery, even though it has been used for centuries as a stimulant by millions of people.
“Despite all of the research that has been done on caffeine in mammals, no one to my knowledge has ever determined why it is present in plants,” said Dr. Nathanson, a neurologist at Harvard Medical School and Massachusetts General Hospital.
“Over time, plants have developed certain defenses to protect themselves against insects, and we suspected that caffeine might have been present for that purpose – as a natural insecticide,” Nathanson said.
“Tests with powdered tea and coffee, as well as with pure caffeine and related compounds, found that they disturbed the behavior and growth of numerous insects and their larvae.”
“The mosquito larvae, for instance, became so uncoordinated with exposure to these compounds that they could not swim to the water’s surface for air and drowned.”
“At concentrated doses, the test substances killed the insects within hours or a few days,” the report said.
“In tests, caffeine distorted behavior, depressed food consumption or inhibited reproduction of tobacco hornworms, mealworms, milkweed bugs, butterfly larvae and mosquito larvae.”
“The scientist also found that when caffeine compounds were mixed with certain other natural insecticides, an increase in their killing power occurred. The potency of the combination, the researchers found, was far greater than that of the sum of the parts.
“In one test, for example, a known pesticide combined with a small amount of a synthetic caffeine compound was 10 times more potent than the pesticide alone, the report said.”
“Dr. Nathanson said caffeine appeared to suppress certain enzymes in insect nervous systems. He said the results raised the possibility of developing caffeine-based insecticides that would be relatively harmless to animals and humans for spraying on food crops.”
‘ “The side effects of caffeine-like compounds appear to be relatively minor in humans and animals,” he said.
“But he cautioned that it might take at least five years for large-scale testing to determine if caffeine-related insecticides were practical and economical.”
Therein lies the rub: Dr. Nathanson’s study was published in 1984, almost 40 years ago. In my research I see plenty of gardening bloggers referring to the study. What I don’t see is news of chemical companies rolling out caffeinated bug-spray products that I can buy at the local market. That would be news I can use.
So my hallelujahs are tempered to that extent.
“Several companies are working on deriving an organic pesticide from caffeine and other similar substances,” wrote Larry Hodgson in a 2017 post on his Laidback Gardener blog.
“Most chemical insecticides are highly toxic to humans and animals as well as insects. They can cause serious illnesses including some forms of cancer,” writes Jonathan Budzinski on gardenguides.com. “Caffeine as a potential insecticide will reduce the threat posed from the use of manufactured chemicals to the human population.”
One sour note (fly in the ointment?) is sounded by Jon Kapecki on quora.com. Kapecki bills himself as a “scientist, technical writer, cook and mostly curious dude.”
“Caffeine will work against garden slugs and snails, according to researchers at the Agricultural Research Service station in Hilo, Hawaii,” Kapecki wrote. “It also appears to repel caterpillars when sprayed on plants.”
“Other insects, like mosquitoes showed abnormal and ultimately destructive behavior or impeded reproduction when exposed to high levels of caffeine.”
“However, at useful concentrations caffeine is basically ineffective against the many insect pests that bear an exoskeleton because caffeine needs to get into the bug to do its dirty work,” Kapecki wrote. “It can also harm other garden creatures, like frogs or earthworms, which may or may not be the gardener’s target.”
Here’s hoping scientists will continue to ponder these things over their morning coffee, and brew us up a solution.
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