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Japanese Beetles Showing up in Central Iowa

July 15, 2015

Here is a post from Dr. Donald Lewis of the ISU Entomology Department to Larry Ginger of American Lawn Care in Des Moines, IA.  Larry had submitted some pictures of Japanese Beetles earlier this week.

 Dr. Lewis is at

Thanks, Larry.

Japanese beetle populations appear to be slowly recovering from their near-complete population crash over the winter of 2013-14.  After seeing almost no JB last summer we are receiving reports from across most of the state, with most observers saying they have seen “a few.”  The exception appears to be western Iowa where slightly more are appearing in some places where they were not previously reported.

This week we have also received a report of activity by adult green June bugs, Cotinis nitida.  These very large, inch-long scarab beetles are highly variable but generally velvety green over most of the body with variable golden-brown markings on the edge of thorax and wing covers.  See BugGuide for photos.

The green June beetle has only been reported in 10 counties within Iowa.  Please send specimens or photos if you see them outside the currently-reported counties:  Harrison, Pottawattamie, Fremont, Page Greene, Polk, Scott, Muscatine, Des Moines, Lee.


Donald Lewis


The first 3 pictures are from Larry Ginger.

This picture of Green June Bug is from Dr. Lewis.


False Japanese Beetle (Strigoderma arbicola) Showing up in Iowa

June 25, 2015

Here is a post from Dr. Donald Lewis, entomologist at Iowa State University.  In recent weeks, we have both been contacted about Japanes beetles (Popillia japonica) showing up in central Iowa.  Don has found that these are actually False Japanese beetles (Strigoderma arbicola). We do get Japanese beetles here, although last year populations were low.

Here is Don's post.

From: Lewis, Donald R [ENT]

Pest identification is a keystone to IPM.  An example going on now is the emergence of False Japanese Beetles (FJB) in eastern and central Iowa.  As the name implies, false Japanese beetle (Strigoderma arbicola) is very similar in appearance to the true Japanese beetle.  The major difference is the coloration.  False Japanese beetles do not have the bright green and copper coloration of the Japanese beetle.  They are dark tan to brown though the thorax may appear metallic green on some specimens.  False Japanese beetles do not have the five white hair tufts that are prominent on each side of the abdomen of the Japanese beetle.   Here is a link to a close-up photo of FJB where these characteristics can be viewed.

The BugGuide website uses the common name “sand chafer” which matches very well the locations where we must commonly see this beetle in fields, gardens and lawns.  However, the common name “false Japanese beetle” has been used in Iowa for at least the past 50 years!  The False Japanese Beetle is moderately common in the state but varies greatly from year to year.  Others are reporting more than usual this year.

Technical information about false Japanese beetle:

An old article about FJB:  Note since 1999 the true Japanese beetle has expanded its range in Iowa to 63 counties (not the 5 listed in the chart).


Donald Lewis

Donald R. Lewis


Department of Entomology

Iowa State University

Ames IA 50011


Dr. Laura Jesse Iles

laura jesse headshot
Plant and Insect Diagnostic Clinic Director
Extension Program Specialist IV
Area of Expertise: 
bugs, ipm, diagnostics