Japanese beetles (Popillia japonica) have been a big part of the U.S. spring and summer scene since the year Albert Einstein presented his Theory of General Relativity. (That was in 1916.)

These brilliant green insects emerge between late May and early June and spend the next six weeks eating, mating, eating, laying eggs … and eating.


The eating part can be a problem. Adult Japanese beetles eat the leaves and flowers of more than 300 plant species2, but they seem to have a particular fondness for ornamental plants beloved by homeowners – like roses.


When these insects chew on leaves, these leaves  release “don’t eat me” chemicals to ward off leaf eaters. But Japanese beetles take one whiff and consider them an “all friends welcome” invite.  It doesn’t take long for a hearty plant to be completely stripped of its leaves and blooms.


Their flowers’ “don’t eat me” chemicals cause temporary beetle paralysis that lasts 12-16 hours. Somehow, Japanese beetles prefer them anyway, and will do the ole eat-and-freeze until they trundle off to better food.

What’s a gardener to do?

Written by Buzz and regular contributor Matt Shipman

Matt Shipman (@shiplives) is a public information officer at North Carolina State University and a freelance science writer. He also writes the Communication Breakdown blog, which focuses on science communication. He lives near Raleigh, in a house full of humans.

Illustrated by Catherine Kehoe Arnold

Art by Catherine Kehoe Arnold. Catherine is a multi-disciplinary designer with a serious passion for craft and beauty. Generating inventive and creative design solutions are my areas of expertise. In her words, “my focus is to create beautiful things in the world and my loves are people and BuzzHootRoar!” Check out more of her work here, buy some of her creations here, and follow her on Twitter 

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1 http://link.springer.com/article/10.1007/BF02035145