Nature Bulletin No. 579   November 7, 1959
Forest Preserve District of Cook County
Daniel Ryan, President
Roberts Mann, Conservation Editor
David H. Thompson, Senior Naturalist

****:THE JAPANESE BEETLE

The deadly warfare between mankind and the insects never ends. Every 
minute of the day and night, billions of them are attacking our crops, 
orchards, forests and grasslands. They attack our homes, gardens, and 
even ourselves. Of those that were inadvertently brought to the United 
States from foreign countries, one of the most destructive is the 
Japanese Beetle.

This pest was discovered in a nursery near Riverton, New Jersey, in 
1916. Evidently some of its grubs -- the larvae-- had arrived a few years 
earlier in earth around the roots of plants imported from Japan. Over 
there, native parasites keep this beetle under control. Here, with none of 
those natural enemies, it multiplied and spread rapidly. Also, before we 
established stringent preventive measures, it was widely distributed in 
shipments of nursery and greenhouse plants. Now it hitchhikes on 
railroad trains and airplanes. Except northern New England, all but 
three states east of the Great Plains are infested by the Japanese beetle.

The adults feed voraciously on more than 250 kinds of plants They 
attack shade trees; the foliage and fruit in orchards; ornamental plants 
such as roses the fruits of berry vines; wild and cultivated grapes; the 
leaves of clover, alfalfa and soybeans; the silk on ears of green corn. 
The grubs destroy the roots of grasses in lawns, golf courses, pastures 
and hayfields. Each year, in damage done and efforts to eradicate it, this 
insect costs us many millions of dollars.

The Japanese beetle is closely related to the sacred scarab beetle of 
Egypt and to the June bug and "tumble bug" in America. The adult has 
a plump, shiny green body a half-inch long, and copper-colored wing 
covers. There are two white spots on the end of its abdomen and five 
more on each side. In our region they appear about the last week in June 
and live from 30 to 40 days. The female deposits four or more eggs in 
each of many shallow burrows she digs in the ground. These hatch into 
small white grubs that feed on plant roots and grow rapidly until, in late 
autumn, they burrow deeper and hibernate. As soon as the soil becomes 
warm in spring, they come up near the surface and continue to feed and 
grow until nearly an inch long. Then they go into a resting or pupa stage 
for 3 or 4 weeks, become adults, and finally emerge. Frequently there 
are from 50 to 150 grubs per square foot of soil and they devastate large 
areas.

In Illinois the first serious infestation occurred near Bessemer Park on 
the south side of Chicago in 1936. There, and in later outbreaks at 
Highland Park, Evanston, Forest View, Decatur and East St. Louis, the 
beetles were eradicated. Last year, an area which extended from 119th 
St. to Sibley Blvd. and from Crawford Ave. to the Illinois Central RR., 
including our Pipe O' Peace golf course and other forest preserve 
holdings, was found badly infested This spring the beetles were 
eradicated by the Illinois Dept. of Agriculture in cooperation with the 
federal government and the Forest Preserve District. This summer, 
however, Japanese beetles were found east of the I. C. RR.; in railroad 
yards at Joliet, Streator, Mattoon and East Peoria; and an area of about 
45, 000 acres near Sheldon, Iroquois county, is seriously infested.

Biological controls of this beetle -- by parasitic wasps and flies, by 
round worms, and by bacteria which infect the grubs with "milky 
disease" have proven ineffective or too costly Insecticides such as lead 
arsenate, DDT, chlordane, and dieldrin have been used extensively. The 
latest, cheapest and most effective method is to spread over an area, by 
airplane and at the rate of two pounds per acre, small granules of a 
toxicant called Heptachlor, They dissolve into the soil, kill the grubs, 
and eradicate this destructive pest.