Japanese Beetles

How to Get Rid of Japanese Beetles in the Garden

japanese-beetle-garden-pest-bug

Use these tips to get rid of Japanese beetles.

Crestock

Japanese beetles (Popillia japonica) are iridescent green beetles that carry a big threat because they will feed on a wide variety of plants. You’ll often be able to identify the damage because their leaf chewing leaves a lacy skeleton. 

What Are Japanese Beetles?

These small insects do not discriminate when it comes to what types of plants they feed on, though they do have favorites (like roses). In fact, they are classified as a pest to hundreds of different species. They are one of the major insect pests in the Eastern and Midwestern United States, causing monumental damage to crops each year.

Prior to the beetle’s accidental introduction to the United States in the early 1900s, the Japanese beetle was found only on the islands of Japan, isolated by water and kept in check by its natural predators. In 1912, a law was passed that made it illegal to import plants rooted in soil. Unfortunately, the failure to implement the law immediately allowed the Japanese beetle to arrive in this country.

Most entomologists agree that the beetles entered the country as grubs in soil on Japanese iris roots. In 1916, these coppery-winged pests were first spotted in a nursery near Riverton, New Jersey, and by 1920, eradication programs were dropped; the beetle proved to be too prolific and widespread. 

Identification

How to Identify Japanese Beetles

Japanese Beetles are ½ inch in length with metallic blue-green heads. They have copper-colored backs, tan wings, and small white hairs lining each side of the abdomen. Japanese beetles usually feed in small groups.

Prior to becoming adult beetles in June, they are 1-inch-long, white, c-shaped grubs live in the soil and feed on the roots of many plants. Often, these grubs are a problem in lawns.

Once adults, they don’t live long but they are voracious. They attack plants in groups, which is why damage is so severe. Although the lifecycle of the adult Japanese beetle is barely 40 days, it can cover a lot of ground. Even if you succeed in controlling your Japanese beetle population, your neighbor’s Japanese beetles might come on over.

japanese-beetle-damage.jpg
Photo Credit: Ohio State University. Japanese beetles cause leaves to appear skeletonized.

Signs of Japanese Beetle Damage

Japanese beetles feed on a wide variety of flowers and crops (the adult beetles attack more than 300 different kinds of plants), but in terms of garden plants, they are especially common on roses, as well as beans, grapes, and raspberries. Here’s what to look out for:

Skeletonized Leaves and Flowers

Japanese beetles chew leaf tissue from between the veins, leaving a lacy skeleton. You’ll know right away when you see leaves that are “skeletonized” (i.e., only have veins remaining). (Mexican Bean Beetles can also leave foliage skeletonized, though, so be sure to identify the beetle by their appearance as well.)

Japanese beetles are not usually far from damaged leaves, so inspect the plant thoroughly. Also keep an eye on the ground beneath the plant; the beetles may reflexively drop off the plant if disturbed.

Unhealthy, Brown Patches in Lawn

Japanese beetle grubs damage grass when overwintering in the soil, as they feast on the roots of lawn grasses and garden plants. This can cause brown patches of dead or dying grass to form in the lawn, which will pull up easily thanks to the weakened roots. 

Control and Prevention

How to Get Rid of Japanese Beetles

Fortunately, good horticultural practices, including watering and fertilizing, will reduce the impact of the damage caused by these beetles, but often times you simply need to get rid of them. Here are some ideas:

  • Hand Pick: Japanese beetles are easy to see and are fairly easy to knock into a can of soapy water. Yes, it’s time consuming, but it’s also the most effective way to get rid of these pests. Just be diligent. When you pick them off, put them in a solution of 1 tablespoon of liquid dishwashing detergent and water, which will cause them to drown. 
  • Neem Oil: We also deter feeding by adult beetles by spraying plants with Neem oil. Neem oil and sprays containing potassium bicarbonate are somewhat effective, especially on roses. The adult beetles ingest a chemical in the neem oil and pass it on in their eggs, and the resulting larvae die before they become adults. Note: Neem can be harmful to fish and other aquatic life, so don’t use it near lakes, rivers, and ponds. It must be reapplied after rain.
  • Row Covers: Protect your plants from Japanese beetles with row covers during the 6- to 8-week feeding period that begins in mid- to late May in the southern U.S. and in mid- to late June in the North. Row covers will keep the pests out, but they will keep pollinators out, too; be sure to remove them if your crops need to be pollinated.
  • Use a Dropcloth: Put down a dropcloth and, in the early morning when the beetles are most active, shake them off and dump them into a bucket of soapy water.
  • Insecticides: If you wish to spray or dust with insecticides, speak to your local cooperative extension or garden center about approved insecticides in your area.
    • Or, try this homemade solution: Mix 1 teaspoon of liquid dishwashing detergent with 1 cup of vegetable oil and shake well; then add it to 1 quart of water. Add 1 cup of rubbing alcohol and shake vigorously to emulsify. Pour this mixture into a spray bottle and use it at ten-day intervals on pests.
      Warning: Homemade sprays can run more of a risk of damaging plant leaves, so be careful and use sparingly. It’s always a good idea to first test a little bit of your spray on a small part of your plant, wait 24 hours to see if there are any adverse reactions, and—if not—proceed with spraying the rest of the plant.
    • Apply sprays in the morning, never in full sun or at temperatures above 90ºF. If your plants start to wilt, rinse the leaves immediately with clean water.
  • Japanese Beetle Traps: Yellow target traps baited with a pheromone attractant work to control large numbers of beetles, but sometimes too well. Don’t place one near your garden or you’ll be pulling beetles in from all over town. If you want to try them, be sure to place traps far away from target plants so that the beetles do not land on your favored flowers and crops on their way to the traps.
    • Fruit Cocktail Trap: You can buy Japanese beetle traps of all sorts, but most are no more effective than a can of fruit cocktail. Open the can and let it sit in the sun for a week to ferment. Then place it on top of bricks or wood blocks in a light-colored pail, and fill the pail with water to just below the top of the can. Place the pail about 25 feet from the plants you want to protect. The beetles will head for the sweet bait, fall into the water, and drown. If rain dilutes the bait, start over. 
  • Use parasitic nematodes in lawns and garden beds for grub control.
  • Plant geraniums nearby: Japanese beetles are attracted to geraniums. They eat the blossoms, promptly get dizzy from the natural chemicals in the geranium, fall off the plant, and permit you to dispose of them conveniently with a dustpan and brush. Plant geraniums close to more valuable plants which you wish to save from the ravages of Japanese beetles. 
  • Nip rose buds and spray rose bushes: Note that insecticides will not fully protect roses, which unfold too fast and are especially attractive to beetles. When beetles are most abundant on roses, nip the buds and spray the bushes to protect the leaves. When the beetles become scarce, let the bushes bloom again. Timeliness and thoroughness of application are very important. Begin treatment as soon as beetles appear, before damage is done. 

For rose growers, see our Growing Guide for Roses for more tips on caring for roses!

japanese-beetle-identification-control.jpg
Photo Credit: Jeff Hahn, University of Minnesota. Sometimes the easiest way to get rid of Japanese beetles is to pick them off the plants before they do too much damage.

How to Prevent Japanese Beetles

Unfortunately, there is no magic potion to get rid of this pest. For general preventive maintenance, experts recommend keeping your landscape healthy. Remove diseased and poorly nourished trees as well as any prematurely ripening or diseased fruits, which can attract Japanese beetles. Try these tips:

  • Choose the Right Plants: Select plants that Japanese beetles will not be attracted to. See our list of the Best and Worst Plants for Japanese Beetles. Dispersing their favorite plants throughout the landscape, rather than grouping them together, can also help.
  • Get Rid of Grubs: In the grub stage of late spring and fall (beetles have two life cycles per season), spray the lawn with 2 tablespoons of liquid dishwashing soap diluted in 1 gallon of water per 1,000 square feet. The grubs will surface and the birds will love you. Spray once each week until no more grubs surface.
  • Milky Spore: You can introduce the fungal disease milky spore into your lawn to control the Japanese beetle larvae population. The grubs ingest the spores as they feed in the soil. The spore count must be up for two to three years for this method to be effective. Fortunately, the spores remain viable in the soil for years. This is an expensive treatment, as all the soil within five-eights of a mile needs to be treated for good control.
  • Beneficial Nematodes: You can also drench sod with parasitic nematodes to control the larvae. The nematodes must be applied when the grubs are small and if the lawn is irrigated before and after application. Preparations containing the Heterorhabditis species seem to be most effective.
  • Plant Strategically: Companion planting can be a useful strategy in preventing pests. Try planting garlic, rue, or tansy near your affected plants to deter Japanese beetles. 
  • Parasitic Wasps: You can also attract native species of parasitic wasps (Tiphia vernalis or T. popilliavora) and flies to your garden, as they are predators of the beetles and can be beneficial insects. They will probably attack the larvae, but they are not very effective in reducing the overall beetle population. 

WARNING: Many dusts or sprays are highly toxic to honeybees, native bees, and other pollinators. If application of these materials to plants is necessary during the bloom period, do not apply during hours when bees are visiting the flowers (late morning through mid-day). If more than just a few yard and garden plantings are to be treated, you may need to contact nearby beekeepers in advance so that they can protect their colonies. 

planting_for_pollinators_webinar_ad.png

Reader Comments

Leave a Comment

Japanese Beetles

I too sacrifice an old rose bush thats away from my other plants and that is also where I collect the bugs and destroy
I regularly spray mixture of Garlic and water on those plants I want to protect
It doesn't kill them but they don't like it.
Let the garlic soak in a separate container for a day or so. You can add other natural deterrents if you wish ( cedar leaves tomato leaves ruhbarb geranium ) Strain the mixture into a sprayer
I chose NOT to use a trap this year .I feel that this year I have had less of a problem without the trap although I cant be certain on the numbers.

Japanese Beetles

I too sacrifice an old rose bush thats away from my other plants and that is also where I collect the bugs and destroy
I regularly spray mixture of Garlic and water on those plants I want to protect
It doesn't kill them but they don't like it.
Let the garlic soak in a separate container for a day or so. You can add other natural deterrents if you wish ( cedar leaves tomato leaves ruhbarb geranium ) Strain the mixture into a sprayer
I chose NOT to use a trap this year .I feel that this year I have had less of a problem without the trap although I cant be certain on the numbers.

Japanese beetles and chickens

My husband goes out a time or two each day and collects japanese beetles in a large yogurt container with just some water in it, no soap. Then he carries it out to our hens. My goodness, the ladies race right for him talking all the way. He reaches into the water and scoops the beetles out, then dashes them to the ground. The ladies jump right on them and eat them all up. They love them, and look forward to their beetle treats every day during japanese beetle season.

THESE BEETLE ALSO LOVE BANANA

THESE BEETLE ALSO LOVE BANANA TREE PLANTS//FLOWERING PEACH TREES///PURPLE LEAF PLUM TREES///AND HIBISCUS .

Japanese Beetles

I discovered they also love hollyhocks. This is the first time I planted them in my garden. I found a mating pair on a leaf and dumped them into soapy water. I also have little sprouts of sassafras trees and those leaves get decimated too. Don't notice any other plants getting eaten so far. I applied milky spore to my lawn in early spring and will again in the fall.

Offering a sacrifice?

We rent a condo and have a tiny garden plot out front, which we use predominantly to grow a few interesting food products like beans, tomato peppers etc. We plant these around a few existing plants that were there before we moved in. And one of these happens to be a rose bush.

I've noticed that Japanese beetles particularly love this rose bush as this article points out. But what we've also noticed, is that they love it so much they stick to it like glue and leave our food items relatively alone and continue to strip the rose bush. So I have no plans on removing that rose bush. Even if it is attracting Japanese beetles, it's distracting them from turning our garden into a graveyard.

THEY'RE BAAACK!

When I purchased my house in North Jersey back in the late seventies, there was a puny, little red rose bush up against a wall. Try as I might, nothing got it to thrive. It didn't help that it was a chick magnet for every Japanese beetle in Passaic county. It finally gave up the ghost and my J.B. problem was over for over 40 years. Lo and behold, I was out early a few days ago and what should I see, but a lone beetle sitting on a peppermint stalk in all his bronzy, green glory! Now if I could have been sure that it would have been content to help eradicate the peppermint patch that is slowly taking over my front yard, I would gladly have let him stay. However, he was dangerously close to my tomatoes, peppers and cucumbers and I wasn't sure if he would find them as tasty as my poor, lamented rose bush. Unfortunately, the story did not end happily for my little visitor.

Milky Spore

The Japanese Beetles would devour my roses and crepe myrtles every year, completely eating the crepe myrtle blooms off the plant! I have a huge yard, and could not apply milky spore to the whole thing, but I put it in the areas around the roses & crepe myrtles, and spot applied it elsewhere. I did this about 2 or 3 years ago. The Japanese Beetle damage last year and this year is almost nothing. I see an occasional beetle, but little to no damage on the plants, and no clusters of beetles feeding on the blooms. Fingers crossed that it continues to work for years to come, but so far so good! While it was not cheap, it will be well worth the investment if it lasts for the 10 years or so that it should.

Japanese Beetles

I chuckled at your suggestion to hand pick them and throw them into a paper cup with soapy water. the soapy water trick is what we used in the 1960’s, in PA.
There is something very satisfying in flinging those nasty little bugs that ruined my roses, into the soapy water and seeing them try to swim. A Ha! Gotcha!

Japenese Beetles

The best solution that I have found to help decrease the population of Japanese Beetles are the bag traps. We have 1 1/3 acre of trees, shrubs & flowers and before getting the bags we tried everything else and the bag traps work the best.

Pest

This is the first year I have seen them in my garden. I am growing potatoes and sweet potatoes and they are just feasting on those leaves. I have some neem oil I will spray the leaves today. Thank you.

Insecticide Mentioned

Is the mixture you mentioned in the article (1 teaspoon of liquid dishwashing detergent + 1 cup of vegetable oil + 1 quart of water + 1 cup of rubbing alcohol ) a pest control for all kind of bugs on plants? Something is eating the leaves on my veggies and herbs and I've seen some kind of beetles in the pool early in the morning.

Japanese beetle

They also like climbing hydrangea!

Japanese Beetles

I've found that Japanese Beetles love Evening Primrose. It grows wild everywhere I garden. I used to rip it up as a weed, then one day saw one covered with Japanese Beetles. Now I let them grow everywhere around my garden and I don't have a problem with the beetles in my vegetables. They would rather eat those than anything else. Plus, they're free. :-)

japanese beetle predator

noticed japanese beetles in my ornamental pussy-willow and crab trees; have been plucking by hand but also noticed the other day 3 cardinals feasting on the bugs---who knew? thanks, red birds; all you can eat, and bring your friends! :?)

Rabbits in the Garden

This may be a little gross for some of you but I have two tricks to keep the small mammals and even deer away from my garden. 1) I ask my barber for the hair clippings when I get my hair cut and sprinkle them around the garden 2) (the gross part) Sometimes I will pee on the outside of the fence edge. The mammals smell this and think it is a predator territory. In 15 years of having a veggie garden ( in CT) . Only edamame plants have every been assaulted by mammals (Whitetail deer)

That time of year again

Those durn Japanese beetles are making their summer pilgrimage to my gardens again. Because my gardens are filled with pollinators, I cannot spray with anything that’s truly effective.
So twice a day I roam the garden paths with a jar filled with soapy water. It takes stealth, but I get great satisfaction tapping singles and mating pairs into my jar. A few escape but most succumb and by summer’s end my jar will be full.
Along with my rose bush, they seem attracted to the leaves of my flowering ginger and lemon balm flowers, which the bees love.
I view it as a meditative time spent among my herbs and flowers. And it’s highly satisfying seeing my jar fill.

California -I found Japanese Beetle Grubs in my garden this year

All the literature I've found says they were only on the East coast and midwest, but I am in the Silicon Valley... I found about 26 in the one garden bed i ended digging up... unfortunately my other two garden beds already had seedlings growing - so I was too late to get them out of those. :'(

Based on this, I think they are now all over the States - very very sad

Japanese Beetles

Japanese Beatles ate my 4 o'clock s. Don't think that they were deterred by them one bit. I guess I should be glad they eat the leaves of my fruit trees and not the fruit. They love the cherry trees the most. You might try planting a cherry tree, I have found if they can eat cherry tree leaves and grape vines they tend to leave the rest more or less alone.

Japanese Beetles on Linden Tree

I'm removing my Linden Tree due to Japanese Beetles and replacing with a Red Maple.
Do I need to treat the soil before planting the new tree?

Japanese Beetles

These beetles are destroying a rose of sharon tree I've had in my yard for over 10 years. This is the first time I've ever had a problem with this pest. I've been knocking them into an empty plastic bottle with some water in it and drowning them. They are pretty easy to catch but so so many! I've pulled up all the grass in my yard this year and have mulched everywhere, I'm wondering if this contributed to the beetle problem?

japanese beetles

I have tried the milky spore. The first year I applied it in early fall per instructions, but was not able to put a second application. It really worked the first 2 years. This year has been a horrific beetle infestation. Probably a couple 100,000 of them. Read more on application of product and will use again but with applications in early spring also. Am also going to try the soap application as well. Thank you. These things are a nuisance.

Japanese beetles

Years ago (60) I went around with my mother with a jar contingent something. We would hold it under the beetle on the rose bush and they would just fall in. Does anyone know what this something is?

Japanese Beetles

The Editors's picture

It was likely just soapy water, or perhaps a mixture with alcohol or vinegar. When they feel threatened, the beetles will often drop off the plant automatically, so simply approaching and holding a bucket underneath them may do the trick.

anyone tried planting 4-o'clocks?

I read somewhere that allegedly JPs are attracted to 4-O'Clocks and will eat the leaves, which are poisonous to them, and die. Just for fun I planted pots of them and placed them near my grapevine, which they also love. I think the plants are too small yet, but I'm interested to see the results. Curious if anyone has actually tried this. Thanks!

4 OCLOCKS TO GET RID OF JB

I HAVE A WHOLE ROW OF THESE FLOWERS IN MY GARDEN. HAVENT NOTICED ANY ON MY BEANS OR TOMATOES. RABBITS ARE EATING OUR GARDEN. TOMATOES, OKRA AND PEAS. ANY SUGGESTIONS FOR THESE CRITTERS1

Rabbits i n your garden

Buy a live trap or two. Bait them. After trapping rabbits, load them in your car and take them far out in the country and let go.. or Bonk them on the head and have them for dinner. NOoooooooooo. Wild rabbit is too much work to cook!

Japanese Beetles

Also, I have a new Azalea bush - do I need to be worried about her??? They don't bother my Elephant Ears or Cannas

Japanese Beetles

I read somewhere that 4 O'clocks kill them - is this true? Also they do not seem to bother my Impatients (S?) or Begoias.

Japanese Beetles

I hope to be getting an earlier offensive attack this year. I have to replace my Crowder Plum this year, but before I do, I think I have to treat the soil. I have bare spots in my grass around my dead tree and I think I have a mole this year!!!!! What is your recommendation as to what to do? I don't want to kill any bees. I just want the Japanese Beetles GONE!!!!

Pages

FREE BEGINNER'S GARDEN GUIDE!

Sign up for our email newsletter by entering your email address.

BONUS: You’ll also receive our free Beginner Gardening Guide!

The Almanac Webcam

Chosen for You from The Old Farmer's Store

Sign up for our email newsletter by entering your email address.

BONUS: You’ll also receive our Almanac Companion newsletter!