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.

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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!

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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. 

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Reader Comments

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Accidental Japanese Beetle Attractant

While trying to reduce the number of annoying mosquitos in my backyard using Repel's Outdoor Camp Fogger, shorty after spraying it around my patio deck, we were swarmed by hundreds of Japanese Beetles. This wasn't just a fluke since it happened several times after using the fogger. Who would have thought a repellant would attract these beetles.

Japanese beetles

I have had massive beetle invasions for going on 6 years. I have had no luck. I start each day with a surgical glove on and a pitcher filled with water and Clorox. Why Clorox ? The fumes seem to over come the beetles so they do not fly away to the next branch, next plant, or at times down my shirt. I am talking thousands of beetles for weeks. They have driven the bees away. I used to have migrating humming birds but that has stopped I had 7-8 feeders that would be covered. The beetles love pussy willows,gold raspberries,clematis,June beauty berries,and strawberries. My grape vines were :one in 2 years. Why am I fighting a losing battle? A corn/bean field adjacent to my land. The farmer seems to be intent on fighting weeds not bugs. It's going to cost him big time as his first time spraying Round up it wiped out my pine tree, 4 arborvitae, my red delicious apples, and an 84 foot bed of strawberries. I am 66 years old and I've prayed each year for relief each Spring. After reading this article I know that won't happen but I'm going to try planting some of the plants suggested .

Japanese beatles

Instead of picking Beatles off plants place plastic cup with soapy water directly under beatle then just touch beatle, their inclination is to fall off plant and fly away , instead they fall into cup.

Soap Solution and dying time

Hello,

When you use the method of soapy water in a cup, what ratio of water to soap do you use? How long do you leave them in the solution? How do you dispose of them?

Sheri

Killing Japanese beetles in soapy water

Hi Sheri,
There's no magic formula. I literally just squirt some dish soap into a jar and then fill it 3/4 of the way to the top with water. You want enough that you can see it's a little soapy, but nothing crazy. The exact amount, brand, etc., don't seem to matter.
You knock them into the jar (or they fall in) and they try to swim around a bit. They usually stop fighting it within a couple of minutes, and then they are goners. I tend to let the jar keep filling up in hopes that the ones that get away are at least haunted by the bodies of their comrades. (This is warfare.)
When I do decide to empty it, I use the lid to create just a little opening to pour the soapy water down the drain. Then, I can dump the wet bodies into the trash, rinse the jar, and be ready to go again. If you're super grossed out, you could toss the whole sealed jar.
Last weekend was the worst here for beetles, so I was getting 12-20 from a single bush every hour that I went to check it. I just kept knocking them all into the same jar.
Hope that helps,
Julie

Japanese Beetles

I have fought these critters for years because I grow roses in my yard. I make the rounds of my rose bushes three to four times a day and spray the bugs with insecticidal soap. It kills them within seconds and is not harmful to any of the good bugs. Today, for instance--I count--I killed over 120. Just spray ' em.

Preferred plants

Perhaps because they are taller, the cherry tree leaves are being selected over the roses. (SE Virginia)

Getting rid of Japanese beetles

Could you give more details about what insecticidal soap spray you use. Is it something you mix? Where do you get the particular kind of insecticidal soap you're referring to?
Thanks,
Paul

Japanese beetles

Is there a certain kind of insecticidal soap you buy for the beetles that you spray on them I have over 23 rose bushes thank you

Japanese Beetles

I was told (not sure who) that Japanese Beetles were beneficial to the garden as they fed on aphids on the rose bushes....I have been reading in this forum where they are pests...What is correct ?

Japanese Beetle Pests

The Editors's picture

Japanese beetles are indeed pests. They feed on leaves and flowers (rose bushes are a favorite), but do not feed on other insects, such as aphids. Ladybugs (also called Asian lady beetles), on the other hand, are voracious aphid-eaters and are a great help in the garden. Get rid of the Japanese beetles, but keep the ladybugs!

Asian beetles - lady bugs

There is a difference between Asian lady beetles and lady bugs. Both eat aphids but lady bugs are harmless and stay outside. Asian beetles get into the house in the tiniest of cracks. Any farmer can tell you their house might be sealed but they still fight Asian beetles all year round. They fly around the rooms, they die and litter the floors, they bite, they stink, and they leave a stain behind sometimes. No pesticide seems to deter them. Even bug bombs can't get rid of them. I have seen them come in swarms out of the bean fields during harvest season. No, they are not the same as harmless lady bugs!

Combat Japanese Beetles

I have used milky spore for many of years & it has really reduced the number of J-beetles in the flower, vegetable gardens & lawn. I lost a good part of my lawn to these rascals, used milky spore after reseeding & have not had a recurrence of the J-beetle infestation.

Hope this helps, Good luck

Japanese Beetles

These horrible beetles love destroying the leaves on my red Japanese Maples. Since these trees are so picky about anything put on them or in their soil, I'm scared to spray them with anything. The beetles also decimate my heuchera and banana plants. I have my dogs in the yard (it's their yard after all :-) ) a lot and I don't want to apply anything toxic to them either. The milky spore bag at my local nursery says poisonous to pets in a warning on the bag as did the neem oil spray. I hand pick when I can, but I'm not always home and these beetles work fast! Any pet safe ideas? Will putting garlic cloves around my plants (not planted, just placed around) help? Thanks!!!!

Safe beetle deterents...?

The Editors's picture

All of our best ideas, including homemade solutions that should be pet safe (thinking dish water detergent spray) are listed above. For example, 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.

However, if you read through responses to similar questions below, you’ll see that hand picking is best.

Or you could install different plants. Adult Japanese beetles feed on nearly 300 different host plants. Yes, roses are the ultimate feast. Other favorites include: flowering cherry and crabapple, zinnias, canna, marigolds, crape myrtle, linden, Japanese maple, and birch. See this page for options that these beetles will not pester: http://www.almanac.com/content/japanese-beetles-best-and-worst-plants

Japanese Beetles

We have a blueberry farm in Georgia. Last year, along with the drought, our plants were ravaged by the Japanese beetles. We are trying the milky spore this year, but my understanding is that it can take a while to really have the full effect. The best quick, although temporary solution I have found is diatomaceous earth. It is available in a food grade version and would be safe for your pets to ingest (even beneficial in killing fleas and other insects that bother pets). It is a powder (ground, fossilized phytoplankton) and you can purchase a small pump to dust it on your plants with. Rather than trying to pick hundreds of the beetles off, I found this much easier. It is not a poison, but an irritant to the bugs. It works its way into their exoskeletons and kills them. You can do a quick search and find lots of information on it and where to buy.

Japanese beetles

Thank you for posting this. I have Diatomaceous earth and use it for ants. When is the best time to apply?

Japanese beetles and fruit crops /leaves and fruit

Hi ! I am excited to try de but want to avoid harming beneficial bees will they be harmed by de ? Do you only apply it at certain times ? Do you know a great source for the price
I have a huge garden etc and would nred A LOT

Source for Diatomaceous Earth

Check your local farm supply places, they sell it as animal feed additive. I paid 14.00 for a 50 pound bag.

Japanese beetles ridding them

If you got the time and patience, follow along. Get a small jar with an inch or two of gas in it, then go Beetle Hunting. After putting them in the gas, they will nose-dive to bottom of jar and on the way will break wind. Seriously, folks I tried this and it WORKS!

Use of gas on jap beetles

The use of gasoline to kill Japanese beetles is not only unsafe and irresponsible it is a VERY stupid thing to do. Use soapy water instead.

Beetles

I've used a 3# 'wide mouth' coffee canister filled with spent motor oil. Once they 'fall' into the wide mouth, game over! Or, you can hand pick the beetles and toss them in. I realize this is like holding an ocean wave back with your hands but, I say it is one less beetle to worry about. Someone wrote about using a spray for mosquitoes and that was attracting the Japanese Beetle. I've also tried the Bag-a-Bug approach but the local raccoon ripped the bottom open. If one were to get a wide mouth container, fill it with old motor oil, and insert a Bag-a-Bug bag leading the the wide mouth....it might just work!

Do Indian Summer raspberry plants need to be winterized? If so,

Do Indian Summer Raspberries need to be winterized? If so, how. I live in Southern NJ.

Winterizing raspberries

Hi there! You do need to winterize raspberries in your zone. Try this:
1
Continue watering the raspberries long after the plants have stopped producing fruit, and don't hold off on watering until the first frost. This extended watering prevents over-drying during the winter and also helps harden the plants and prepare them for the cold.
2
Remove any of the brown canes that produced fruit during the summer but leave the green canes alone. When pruning the canes, cut them down to the soil level.
3
Bury the remaining raspberry canes if these are new plants that haven't experienced winter yet, as these plants are extra-sensitive to winter's chills. Push the flexible canes down to the ground and bury them under a couple shovelfuls of dirt.
4
Erect a simple fence barrier around the raspberry bush, as raspberries attract rabbits and other pests during the winter who like to feed on the plant's stems. Use traditional 1/4-inch mesh wire, which you can buy at garden stores and nurseries. The fence should go 3 inches into the soil, to keep rabbits from digging under it, and stand 20 inches above the soil to keep rabbits from jumping over it.

Things You Will Need
Pruning shears
Garden spade
1/4-inch mesh wire

Some raspberry varieties have thorns, although most domestic varieties have had this tendency bred out of them. If your raspberry bush has thorns, wear gloves and a long-sleeved shirt to protect yourself when handling the plant.

beetles

I live in Maine and found beetles eating my chamomile; plus other plants. I was told they were Japanese Beetles, but they looked liked coffee beans; they did not have the green metallic. They are in the soil...many of them. Do you have any idea what type of beetle it is?
Thanks, Annie

False Japanese Beetles

The Editors's picture

They could be sandhill chafers, which strongly resemble Japanese beetles, but without seeing them, we can’t say for sure.

Japanese beetles

A type of milkweed plants were covered/infested
with these beetles this morning at Home Depot on Atlantic Boulevard this morning in Jacksonville, Florida. It was brought to the attention of the employees.

Japanese beetles

I just went out to deadhead some geraniums - they did not fare well in recent storms - and found several Japanese Beetles nibbling away. I am surprised since geraniums are not often targeted by insects. Any comment?

Japanese beatles

Thank you for the info.

Japanese beetles

Over several days, I have been hand-picking scores of Japanese beetles off my young trees and rose bushes and dropping them into a bucket of soapy dish water effectively killing them. My question is this: are these beetles coming solely from my property or are they coming from neighboring properties as well. If they are coming mostly from my property, based upon my kill rate, then my lawn must be loaded with them?? Yes or no

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