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Japanese Beetles: They Feed in Groups and Will Leave Your Plants Looking Like Skeletons

Dorothy is a master gardener, former newspaper reporter, and the author of several books. Michael is a landscape and nature photographer.

A Japanese beetle sits nicely atop a dime, but one can't help but want to use that dime to mash his little guts out before he has a chance to destroy some beautiful plant.  Heck, he only gets to live for about a month anyway...

A Japanese beetle sits nicely atop a dime, but one can't help but want to use that dime to mash his little guts out before he has a chance to destroy some beautiful plant. Heck, he only gets to live for about a month anyway...

I Saw Those Guys in 'The Mummy!'

Japanese Beetles look like they just finished their role in "The Mummy" as ancient Egyptian scarabs. They were deadly in the movie and they will wreak havok on your landscape.

  • If your urban landscape has been invaded by adult Japanese Beetles, you are not likely to overlook the damage. These little pests feed in groups. They will start at the tops of a plant usually, and feed downward.
  • When Japanese Beetles emerge from the ground and head toward your plants, beware, for when they are done, the leaves of your plants will look pretty much like skeletons - stripped clean of all tissue that lies between the veins of the leaves. Luckily, a beetle only lives about a month or so and does very little damage when he eats alone.
  • The problem is that they never eat alone...they eat as groups and don't stop as long as there's any leaf tissue left to eat. Japanese Beetles are about a half-inch long and have a metallic brown look to them. Their wings look almost like they are made of copper. Under their wings on each side are white little fluffs of hair.
This is a photo of a Japanese beetle that has just landed on a flower.  Don't let this beautiful loner deceive you, he hasn't begun to eat yet, and I'm certain his whole family is nearby.  They start at the top, then work their way down.

This is a photo of a Japanese beetle that has just landed on a flower. Don't let this beautiful loner deceive you, he hasn't begun to eat yet, and I'm certain his whole family is nearby. They start at the top, then work their way down.

But after a while, your leaves will start looking like this.  There is no end to the damage that Japanese Beetles can do to your plants.  Get rid of them!

But after a while, your leaves will start looking like this. There is no end to the damage that Japanese Beetles can do to your plants. Get rid of them!

You Will Only Need a Few Things

* Soapy water in a bucket

* Japanese beetle traps

  • If you live in an area where Japanese beetles are abundant (and you would know), simply don't grow the plants they love, which include roses, Japanese maple trees, Norway maple trees, grapes and purple-leaf plums, to name a few. But don't despair, because there are a lot of plants that Japanese beetles DON'T like, which include silver maple trees, boxwoods, butternut, holly trees, green and white ash trees, flowering dogwood, persimmon and several varieties of oak trees.
  • If you absolutely have to have some of the plants that the Japanese beetle loves, you could set out traps. Japanese beetle traps are sold in a lot of nurseries and they attract the beetle with two different kinds of bait. The first is the scent of virgin female Japanese beetles that the male beetle finds irresistible. The other smell is simply some sweet-smelling food and it will attract both sexes. These commercially-available traps have been known to catch hundreds of beetles in a single day because the attractive smell is so strong.
  • It is a good idea to keep the traps away from the plants you are trying to protect, because the traps have also been known to attract more than they catch, so the ones that don't get caught could do some serious damage to your nearby plants that they might never have known existed until you put out the traps.
  • You can always remove Japanese beetles by hand. Do your best to keep them from accumulating on your plants, because beetles attract beetles and those beetles attract more beetles, and so on. Japanese beetles are a bit sluggish early in the day, so one way to effectively slow them down is to simply shake them from the plant. If you are able to shake them off into a bucket of soapy water, they will be gone for good. If you shake them off onto the ground, they will just climb right back up on your plants.
  • As a last resort, you can use chemical control. Many insecticides are labeled for use against adult Japanese beetles. The key ingredients to look for are pyrethroid products such as cyfluthrin, bifenthrin, deltamethrin, lambda cyhalothrin, esfenvalerate and permethrin. Before you buy a chemical insecticide for controlling Japanese beetles, however, make sure to ask your local plant professionals if that product is recommended in your growing zone. As is usually the case, all ingredients don't work in all zones.
This Japanese beetle is doing what he does best - terrorizing your plants!

This Japanese beetle is doing what he does best - terrorizing your plants!

You can't look at this photograph and not hate these little garden terrors!

You can't look at this photograph and not hate these little garden terrors!

Great Video on Controlling Japanese Beetles

Japanese beetles are destructive little demons.

Japanese beetles are destructive little demons.

Tips

* If you choose chemical control, treat all foliage and flowers.
* Spraying insecticidal soapy water is usually ineffective against Japanese beetles, as is garlic, hot pepper and orange peels.
* Adults AND grubs can cause considerable damage to your plants. This article addresses the adult Japanese beetle because it is capable of flying into your garden from other areas. Control of grubs will be addressed in other articles.


Scroll to Continue
  • The Japanese Beetle: Everything you Wanted to Know
    The Japanese Beetle is a small bug that looks fairly innocuous. However, it has come to be considered quite a pest in the United States due to the fact that it destroys plants on farms and in gardens. As a...

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2011 Mike and Dorothy McKenney

Comments

becky on July 25, 2011:

luckily i don't think we have these pesky creatures !! i've never seen a leaf that actually looks like a spider web, but will certainly keep an eye out -- are they native to the south usa ?

Mike and Dorothy McKenney (author) from United States on June 02, 2011:

Thanks to you all!

DeborahFantasia from Italy on June 02, 2011:

Great article, very informative !

Cindy A Johnson from Sevierville, TN on May 28, 2011:

It's not quite beetle season where I live but last fall I planted garlic in the areas where I had the most problems with the critters. We'll see how it works - and if it doesn't - we love garlic, anyway.

Mike and Dorothy McKenney (author) from United States on May 27, 2011:

You bet! Thank you for stopping by!

Deborah-Diane from Orange County, California on May 27, 2011:

Wow! This is really helpful! I think I may have had some Japanese Beetles on some of my outdoor plants. I'll try the soapy water and see what happens. Thanks!

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