Japanese Beetles

How to Identify and Get Rid of Japanese Beetles in the Garden

japanese-beetle-garden-pest-bug

Use these tips to get rid of Japanese beetles.

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What are those iridescent green garden beetles eating your plants? Here are tips on how to identify and get rid of Japanese beetles.

What are Japanese Beetles?

Japanese beetles (Popillia japonica) are small bugs that carry a big threat. They do not discriminate when it comes to what types of plants they feed on. 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 a breeder. 

Identification

How to Identify Japanese Beetles

Japanese Beetles are ½ inch in length with metallic blue-green heads, copper backs, tan wings, and small white hairs lining each side of the abdomen. Japanese beetles usually feed in small groups. They lay eggs in the soil during June, which develop into tiny white grubs with brown heads and six legs that are up to ¾ inch in length. These grubs will remain underground for about 10 months, overwintering and growing in the soil.

They emerge from the soil as adult beetles and begin feeding the following June. They usually 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.

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 they are especially common on roses, as well as beans, grapes, and raspberries.

Skeletonized Leaves and Flowers

Japanese beetles can devour most of the foliage on favored plants, as well as the flowers. Look for leaves that are “skeletonized” (i.e., only have veins remaining). This is a tell-tale sign of Japanese beetles. (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

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

  • 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.
  • Hand Pick: Unfortunately, the most effective way of getting rid of Japanese beetles is to hand pick them off of plants. It’s time consuming, but it works, especially if you are 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: 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.
  • 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 safe 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. Homemade sprays can run more of a risk of damaging plant leaves, so be careful.
    • 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.
  • Traps: Japanese beetle traps can be helpful in controlling large numbers of beetles, but they also might attract beetles from beyond your yard. Eugenol and geraniol, aromatic chemicals extracted from plants, are attractive to adult Japanese beetles as well as to other insects. Unfortunately, the traps do not effectively suppress adults and might even result in a higher localized population. 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. 
  • Geraniums: Japanese beetles are attracted to geraniums. They eat the blossoms, promptly get dizzy from the natural chemicals in the geranium, fall down, 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. 
  • Japanese Beetles on Roses? 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. 

NOTE: 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. 

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Reader Comments

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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?

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

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!!!!

Eliminating Japanese Beetles

Julie,

Try something called Milky Spore. It is a little expensive, but lasts about 15 to 20 years before you have to re-apply it. Get the powder not the granular. Powder needs to be applied only once around September. The granular needs to be applied 3 times during the application year. You front load the cost but are done. It is a bit of a pain to put down, but well worth! and it does not hurt anything except the targeted organisms. Kids, pets, us, fish, birds, worms, honeybees, etc. are not affected!!!! The milky spore gets into the ground, the Japanese Beetle grub eats it on the roots, the spores multiply and POOF the grub explodes releasing even more spores! We have done this with two properties with great results. The more grubs, the more spores. The best cycle I can think of. First year you will see a reduction of the beetles. The next year they should pretty much be gone. If you live in a community, you may be able to talk your neighbors into applying it to their land as well. Everyone benefits. Bonus - it also gets rid of June beetle and earwig grubs as well. Aaand, wait there's more. It helps get rid of varmints like moles, skunks, raccoons, etc (provided there is no other food source like the grubs). No grubs, no food. No food, no moles, skunks, etc. We get ours from St Gabriel Organics. We have no affiliation with St Gabriel's Organics. It's just a great product. They make the milky spore. You can buy it from a vendor, but they will just get it from St Gabriel's Organics. Some of the other vendors may be less expensive.
Hope this helps.

japaneese bettles

Glad to see someone was using the beetles for food for something. I have been feeding the fish in my pond with them. They go crazy over them. I am getting tired of picking them off my beans, fruit trees and hazelnut bushes. Considering the trap method, fish would like more for sure.

beetles

Ive been catching tons this year in a bag trap...the thought struck me to just take the bag off in the evening and toss it in the freezer..kills them quickly..then the chickens have a treat in the morning...they do stink horribly if you leave them in a bag too long...my 2 cents

japanese beetles

Last year I worked hard at hand picking Japanese beetles. Several times each day I would go out and hand pick them. I had some Virginia ivy - 5 leaves - which the beetles loved to chew. I would often lean into the vines to get the beetles. One evening while I was getting more beetles and leaning into the vines, I began to feel itchy. (I had worn jeans, a blouse, socks and and regular shoes outside.) Within 1 hour, my breast was very itchy and I took a look at myself and had to call my husband. I don't know if what I had were welts or hives on my breast and chest. Whatever I had continued to spread down to my mid legs. My arms, private areas, face, neck, and most of my back were spared. My husband put calamine lotion on me. I sat in front of the fan and had ice packs on me. The itch was very intense. Much worse than poison ivy. After about 6 hours the itch went away. And within 12 hours of the initial manifestation of the welts or whatever, I had small red dots which didn't bother me a bit!!!! Any idea on what caused all this?? We have 1 pin oak tree, but it is about 2 acres away and a lot of buildings and plants between where I began to feel itchy.

Ivy climber poisoning

My husband had exactly the same thing happen to him. An ancient oak dropped a massive branch which my husband went to clear and chop up on a warm day. Whilst there, he decided to cut back ivy climbing up the oak choking it and a silver queen holly growing beside the oak. He leaned into the ivy, cutting, pulling, and after 1 hr of hard work perspiring, he started to itch. He was not wearing gloves and got dusty, dirty and sticky from the ivy. He felt an itch on his neck and scratched at it and rubbed the dust off his stomach where his tee-shirt had rose up. He felt so awful with intense itch, he came in to wash in cold water but the itching got very intense and where he had touched himself a vicious rash appeared and spread. His stomach, his arms, his neck, and upper body. We used antihistamines, dabbed the areas with cotton wool balls soaked in witch hazel, and smoothered it all in calamine lotion twice a day and before bed. The itching became bearable within 3 days but continued until the rash had faded leaving him with red dots. He will be wearing gloves from now on when he has such work to do, and a face mask so he does not breathe in any spores.

Virginia

This also know as Virginia Creeper. Some people are allergic to this just like poison oak and poison ivy.

Beetles stripped my ornamental plum tree

Last year (2017) the beetles completely stripped my beautiful ornamental plum tree. Even though we treat our yard in the spring and fall, with Grub-X, it's of no use because neighbors don't treat. This year, due to the mild winter (Virginia) they are even worse than last year. Out of desperation, we did purchase a "beetle bag". Despite the fact those bags fill up every day, my poor tree looks terrible. Every leaf is filigreed and once again badly damaged. I sure hope my tree can withstand yet another year of damage.

I am going to try some of the "recipes" for natural trapping, as well as planting catnip and/or chamomile under the tree. Hopefully the beetles won't come near my tree.

There is another species of beetle, which looks like a JP on steriods. This beetle is about 3x the size of a JP, and stupid. They crash into the side of our house numerous times, before they realize they can't fly through. DUH

JP Beetles

After over 5 years of continual Japanese Beetle assaults on my ornamental Crowder Plum, they have finally killed it. Going to try a Redbud next. The other copper colored big beetle you are referring to, I think it's what Kansas people (me!) refer to as June Bugs maybe. They really are dumb!!!! LOL!!!

Plum tree

I had a plum tree that was just starting to produce fruit. I went out to the car one morning and seen all this black stuff all over it and looked around and my tree was completely filled with JB's.
Every leave was gone. Because it was located near my septic tank and the problems the roots could cause i desided to cut it down and put grub killer down .because with what looked like a billion JB's i didnt want to have it distroy any outher fruit trees in the yard. If you want to try to save it beause of the need for leaves to keep the roots alive you need to put grub killer around the tree and the width of the canopy of the tree.

Another trick on the beetles

I put just a little bleach in a bucket of water and floated one of the beetle bait lures on top of the water. I put the bucket on the ground under a trap. It is catching them! When the top is covered, I take a flower pot with holes in the bottom and scoop them out, let the water drain, then put them in a plastic bag. Good bye beetles.

Beetle Traps

I just hung a beetle trap yesterday at 10:30 in the morning. I had one bag full in 2 hours. Two hours later, another bag full and 2 hours after that another bag full and one more bag after that so in 8 hours, I had 4 bags full. I put a bucket of the fermented water mixture under the trap and some got in it but overnight, a raccoon turned the bucket over. I will see how many I get today.

Beetles by the bagful!

Oh, my! It sounds like the air is thick with swarms of beetles, Marty! Is this normal where you are??

Beetle traps

I first saw them about 3 years ago. There was a soybean field across the road from me so that may be what brought more in. I was really shocked to see that many! I was trying to get them off my elderberry bush. I did hear there was a couple down the road that has a Mimosa tree that is covered with them. This morning I have already filled two more bags. I am curious to see when they will slow down. I guess the more I get rid of this year the less there will be next year.

Beetles

I have been getting two filled bags a day for past two weeks. Can not imagine where they all are coming from. Only had them past 3 years. My question is what can I do twitch them , they stink so bad I can’t put in my trash cans and I feel bad for the trash men. Any ideas??

japanese beetle traps

Can you send pics and info on how to make your traps that work thanks

Japanese Beetle Traps

I purchased the Japanese Beetle trap. It comes in a box with 2 bags and the bait lure. It has directions for putting it together and you hang the bag on the hooks at the bottom. I also purchased a bait lure separately that I float in the bucket.

Jap beetle trap info

Thanks so much!

japanese beetle traps not a good idea

Trap LURE the beetles. That's why your "traps" keep filling up.

I went to Sutherland's and

I went to Sutherland's and bought a Japanese/Oriental Beetle trap and the results were amazing! In about 12 hours the bag was full. I wish I had bought more.

What to do when the beetle bag is full

Try the fruit cocktail trick (noted above and repeated here, for expediency): Get a can of fruit cocktail at the grocery store. 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. 

When beetle bag is full

Since I had so many, I laid the bag in the sun to let the beetles die then I empty that bag into a ziploc bag and zip them up and I can reuse my trap bag over and over.

I wish you had too, then I

I wish you had too, then I wouldnt have so many in Nebraska

Japanese Beetles take over central Iowa

I noticed hundreds of these bugs all over a large tree (I don't know what kind of tree) and it was practically devoured by the bugs. They moved on to another tree just like it. I found this website and made the natural mixture. soap, oil, water and alcohol. I sprayed the trees at sundown. I couldn't tell if there were any beetles on the trees or not since it was getting too dark. Do they hide at night?
I will let you know tomorrow if it did the trick
Thanks for the information.

Iowa girl

are beetles active at night?

Research suggests that the beetles are most active on warm, sunny days between the hours of 9 AM and 3 PM but they also may feed at night.

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