It's Japanese beetle time again

StoryImage( ‘/Images/Story//Auto-img-112429767029149.jpg’, ‘Photo by Dr. Robert A. Hedeen’, ‘Pair of Japanese beetles engage in the mating process while others devour a leaf on birch tree.’);

The blade of my putter struck the golf ball with a reassuring click and launched it on a direct line to the hole in the green some 20 feet away. I watched with confidence as the ball rolled toward the cup, feeling sure it would drop in and give me a birdie on the par 5 hole. But, it was not to be. A few inches from the cup the ball encountered some foreign object and veered sharply off to the left, missing the hole by an inch or two. When I made an inspection of the area around the hole, I discovered that my perfect putt had been deflected by a pair of Japanese beetles blissfully engaged in the mating process. At that moment, I evoked the heavens to eradicate all Japanese beetles from the face of the earth. If we could deport undesirable insects as we sometimes do with undesirable people, the Japanese beetle would be first on my list for expulsion.

This Asiatic immigrant first showed up on our shores shortly before 1916 when it was discovered in a plant nursery in Riverton, N.J., just across the Delaware River from Philadelphia. It is presumed to have made its way to this country in the roots of imported perennial plants, such as the iris and azalea. As it had no natural enemies, it quickly flourished in its new environment, and is now a major pest in most of the lower 48.

Many believe the untrue story that when the Japanese gave us the cherry trees to enhance the aesthetic beauty of the Tidal Basin in Washington, D.C. they included a breeding stock of the beetles along with the trees.

Ironically, the adult beetle is rather attractive. The body is basically iridescent green with the wing cases being coppery. There are two white spots on each end of the abdomen, and five more along each side.

Sometimes 50 or more males and females will ball together in a mating orgy, and after fertilization, a female deposits three or four eggs in the soil. She will continue to do this for about a month and will lay approximately 50 eggs during her lifetime. The eggs hatch into tiny grubs or larvae, which feed voraciously on the roots of grasses and other plants and, as a result, grow rapidly. The grubs are one of the most destructive pests of golf courses, pastures, cemeteries, parks and home lawns. In late autumn, the grubs are mature and dig deeper into the ground and pass the winter in a state of suspended animation.

As soon as the soil warms in the spring, they awaken and move to the surface and resume feeding. The quiescent pupal stage is next, and allows the grubs to metamorphose into adult beetles. The adults emerge in this area about mid-summer, and immediately go to work attacking more than 250 different species of plants.

The infestation of Japanese beetles this year in the Rock River Valley appears less than what I have observed in the past. However, a white birch tree in the front yard of my son’s home and a river birch in my yard have been hard hit by these insatiable beasts. A leaf is quickly stripped of the green, vegetative areas, leaving only a skeleton of veins remaining. Such a leaf dies quickly.

Japanese beetles are very difficult to control with insecticides. The long lasting chlorinated hydrocarbon types of insecticides did a fair job before they were banned for general use some 35 years ago. A bacterium, however, causes a condition known as milky disease in the beetles, and eventually kills them. It is non-toxic to humans and is available commercially in powder form.

A pheromone-type sex attractant combined in a plastic trap is available in garden centers and will entice great number of these bugs to their doom. Though this air-borne sex hormone will entrap a lot of beetles, many will not be caught. Those that avoid the trap will set up housekeeping in the immediate vicinity and exacerbate the homeowner’s problem.

I encourage my neighbors to utilize these traps, but I never employ one in my own yard, for obvious reasons.

Dr. Robert Hedeen is a former resident of Maryland’s eastern shore and resided in the Chicago area from 1960 to 1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.

From the August 17-23, 2005, issue

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