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Emerald ash borer is a slender insect about one-third to a half-inch long. Its body is widest just behind the head and then it gradually tapers back to the tip of the abdomen.

Japanese beetles often confused with more harmful emerald ash borer, U of M expert says

August 3, 2011

Minnesota has been on high alert for the emerald ash borer since it was first discovered here in 2009. But experts recently have been inundated with reports of emerald ash borer sightings and are finding it a case of mistaken identity. How can people tell the difference between the emerald ash borer and other, less harmful insects? A University of Minnesota expert who can comment on emerald ash borers is:

Jeff Hahn, Extension entomologist

“Not every green insect is emerald ash borer,” Hahn says. “This summer Japanese beetles have been very common in the Twin Cites as well as areas to the south and southeast. They are often mistaken for emerald ash borer.”

Unlike the destructive emerald ash borer, which threatens the health of the state’s 975 million ash trees, Japanese beetles do not usually cause lasting damage.

To view a photo chart that compares emerald ash borer with the Japanese beetle and other look-a-likes, visit www.extension.umn.edu/go/1074 (PDF). Emerald ash borer is a slender insect about one-third to a half-inch long. Its body is widest just behind the head and then it gradually tapers back to the tip of the abdomen.

“What really stands out about emerald ash borer is its bright, iridescent green color,” Hahn says. “And if it lifts its wings up, you will see the body underneath is a purplish-magenta color.”

By contrast, Japanese beetles are broadly oval, about three-eighths of an inch long with a bright emerald green head and upper body. Japanese beetles also have shiny bronze-colored wing covers. An easy to way to identify a Japanese beetle is by the five small white tufts of hair along each side of the abdomen and two larger white tufts on the tip of the abdomen. No similar insect has those spots, according to Hahn.

To interview Hahn, contact Catherine Dehdashti at (612) 625-0237 or ced@umn.edu; or Preston Smith at (612) 625-0552 or smith@umn.edu.

Expert Alert is a service provided by the University News Service. Delivered regularly, Expert Alert is designed to connect university experts to today's breaking news and current events. For an archive and other useful media services, visit umn.edu/news. Views expressed by experts do not represent the views of the University of Minnesota.

Tags: Extension

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