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

Got iridescent green beetles feasting on your roses? Those would be Japanese beetles! Here are tips on how to identify and get rid of Japanese beetles.

What Are Japanese Beetles?

Japanese beetles (Popillia japonica) are small insects that carry a big threat. They 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, copper-colored 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.

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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 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 impact of 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 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: 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 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. 
  • 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!

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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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japenese bettles

where can i get milky spores?

Where to get milky spores

If you are near an ACE Hardware store, check there. Otherwise check Amazon they also have Milky Spores. Nematodes seem to be a nice natural way to combat Japanese Beetles. Easy to apply if you follow the directions for spraying. Remember to remove all filters from your sprayer so the Nematodes get out. Follow directions for time of day. You can tell if your efforts are effective, the skunks and raccoons will stop digging up your lawn to get at the grubs for food.

Milky Spore

Check with Lowes. If they don't have they can order it in for you. There are 2 types. One is a powder, the other is pellet with something mixed in so you can put it in a broadcast spreader. You can buy it online, but the shipping adds quite a bit to the total cost.

A crush on J.B.

Thank you so much , Stacy , for your terrific trick on the J.B. !
Perhaps we dò need to get a little bit more down to earth .
Good luck with your crush :op

milky spore

I completely agree with the use of milky spore... but it has no impact on the actual adults feeding on the flowers and bushes, but rather to stop the cycle and the damage to YOUR turf from the JB grubs. Unfortunately, you are only stopping the cycle in your own yard, next year the JB's will still be munching on your plants unless ALL of your neighbors do it as well. Wish we could do a widespread milky spore treatment across all of the states they occupy and completely eradicate them!!!!

beetle squashing

I just read on Wiki-how not to squash the beetles. It releases Pheromones (female beetles) which Attract other beetles. Ick! It also said to avoid using traps; they also can attract them. I didn't have any but today I do. I suspect that the strawberries (overripe) attracted them.

Beetle Battle

Stacy I agree that there is no greater satisfaction than crushing the beetle with your fingers but my local nursery said that when you crush the beetle it lets off a scent that attracts other beetles. That is why drowning them is a better solution. Good luck.

I tried growing roses the

I tried growing roses the first time ever, and the JB's devoured them. Late August now, and they are finally mostly gone, its amazing.
I have read somewhere that if you use a blending container only for this purpose, put a large amount of dead beetles in, and liquify them (I know it's gross), spray your plants, and the smell of the dead ones will repel any more.
also how far is far enough from the garden to put the bait lures? Is 2-3 acres away enough?

Japanese beetles

I fail to understand the logic presented by experts who discourage using the Japanese beetle traps!! Of COURSE they are going to attract them! That's the main idea...trap them and then they DIE!! I cannot imagine going out to my raspberry garden and hand-picking thousands of these beetles off my plants every day! I have THREE traps going constantly, between my patch and my neighbors, emptying them every day, and sometimes more than that. In addition, I daily attack the ones that are feeding on leaves with my Hudson sprayer directly. If one could figure out how many of these devils I have killed off this summer, it would have to be thousands and thousands an thousands....that are NOT laying eggs now to produce more!! I think the traps are effective for about a 50 ft radius, as my other plants in the yard and my neighbors are free of infestation. SO the beetles seem to be concentrated in the raspberries, mine and my neighbors patches where they have been laying eggs for 3 years. I first spotted them about 3 years ago, and wondered what they were. I should've started killing them then, but after 3 years of going to ground and laying eggs by the millions, it's no wonder that we have the problem we have now. I intend to treat the ground under and around my raspberries and the surrounding area with grub killer this fall and next spring and summer. I researched which ones are the most effective, and hopefully next year I will have fewer beetles. But this is WAR folks. We are not ever going to be rid of these things completely, so keep on the offensive. Kill them on the leaves, Kill them in the traps, and Kill them in the ground!!

Japanese beetles

I have also been bombarded by the beetles and have sprayed and used traps. My question is, do they end up in the traps before or after they have laid eggs? Or both?

what abou tthe eggs?

The Editors's picture

The answer is a little of both, JL.Many females will lay eggs near the traps, creating problems next year. Read the advice above as well as the comments below. There is a lot of beetle wisdom here!

Detergent method of killing

If I put the mixture of vinegar, sugar and liquid detergent in a small pail with handle, can I hang it on a shepherds hook or does it have to be on the ground?

Detergent Beetle Trap

The Editors's picture

Yes, you may hang the trap from a hook. The beetles are attracted to the smell, so it doesn’t really matter where the trap is, as long as it’s accessible.

Kill Japanese beetle

Use dawn dish soap, put 1 oz per gallon of water. Spray them . They will drop over dead.
This is the best way I find it out. Try it. It works.
Good luck.
Ron

Japanese Beetles

Dawn detergent and water is wonderful!!! The JP’s just fell dead. Thank you so much for the advice. I was about to scream. They wete destroying my flowets.

Jp beetles

How often did you spray Ronnie Parker

dawn soap

Is it harmful to any other plants or bugs?

Japanese Beetles. Grrrrrrr

I have been cutting our lawn about once a week due to all the rain we have had in SE Wi. One week ago my trues looked healthy, in fact we had a lawn service actually servicing our /trees and shrubs. On Tuesday, 7/25, I went out to mow the lawn and I noticed our River Birch had lost 2/3 of it's leaves. They have also attacked our American Larch, Goldrush Redwood, Crabapple Tree, Plum Tree, our Magic Spirea and starting some of the Maples. I am just SICKENED at the amount of damage they have done. So far they have left our Dakota Arborvitae and our Green and Gold Arborvitae alone. We have since called "said" lawn service to come out to re-spray again. Why has this not taken care of them? Will our trees recover? At what point is the decimation beyond the point of no return? We have a LOT of money in these trees/shrubs and the "service" has a guarantee. What do we do now?

japanese beetles

How do you pick the beetles off of a 50 foot tree. And how do you spray or kill the beetles 100feet in the air. I keep them out of my house only by using a electric bell in howell thing that makes a sound through the house and they don't come in but when I go outside they bite and the bite is a serious sore that I now have had on my skin more than 3 months. Nothing works to stop the itching, blisters that burn and run. One bite makes a sore 2 inches in diameter. All leaves are on the ground and the grass is being eaten everything in their path is dead.

Japanese beeltes

Japanese beetles are so bad in central Illinois they just move fron tree to tree eating every leaf and killing everything in their path. The bite from these bugs causes an infection on your skin that is painful and is hard to heal. It turns red, blisters, does not heal well. Leaves a large sore on the skin, itches and burns to touch, nothing stops the pain and blisters. The trees are dying everywhere from these beetles as they eat everything in sight. What will stop them, how do you kill them. Huge trees dying from town to town. What can be done?

Patsy Mccleary... are you

Patsy Mccleary... are you sure that it's Japanese Beetles that are biting you and trying to get in your house? I live in Maryland, and I can not recall a summer w/out dealing with them in 53 years, and my father is a sod-farmer so he deals with their grubs past the summer. That being said... I've never (or have I known anyone) been bitten by one, or had them try to get in the house. They have gotten in the house but only because they latch onto our shirts or hair and we don't know it.... which freaks me out lol! Where do you live?

Yes, indeed, they do bite

A Japanese beetle had gotten on my ankle. When I realized it, I tried to repeatedly knock it off. It was rather tenacious and during this time, it bit me several times. The bite marks were very noticeable. An all-around nasty bug.

Japanese beetles

I noticed we have Japanese beetles in our apple tree, the apples are falling and the leaves are getting eaten, what would you recommend ?

Japanese beetles and apple trees

The Editors's picture

Traps are not always effective for fruit crops because they attract the beetles from miles around and many females will lay eggs nearby, creating problems next year. To get rid of the beetles, there is a wide range of insecticides for the immediate control of beetles—from the broad-spectrum insecticides (eg., Sevin) to the organic options. See this page for examples: http://msue.anr.msu.edu/news/managing_japanese_beetles_in_fruit_crops but check with your state’s cooperative extension to see what’s permissible and advised where you live. In the future, to avoid this pest: 1. Reduce weeds. Apply an herbicide in the fall. 2. If you put down any sod between apple trees, remove grass and use a non-grass cover crop and restrict irrigation in areas near the tree(s) and use a drip system to reduce the habitat for these beetles.

I have effectively controlled them with

I have used a bag trap with pheromone attractant. But I cut the bottom off the bag, put a three inch pvc pipe going into a 55 gallon barrel and bag. It brings in a ton of beetles but they all come off my foliage and trees. It will fill up a couple of barrels in a season, but it saves my garden. I garden an acre of vegetables and fruit trees. I also use a kaolin clay called surroundDT from Johhny's Seeds. Totally non toxic.

When I put the modified bag trap out the beetles come in swarms, go into the trap, down the pipe, into the barrel, and they die in the barrel. I have a hole for the pvc pipe cut into the lid of the barrel. This method has worked for a few years

Thank you

Thank you! Excellent idea!!
I think I'll see if the guy who owns the pasture near me will let me put a barrel trap on his land, he just grazes cattle, no gardening, and it's away from the gardens the rest of us have, but close enough to lure them, perhaps.

Jb

wouldnt it be wise to have the state ppl as well as others put barrels out all over the state and others as well seems to me it would be a cheap way to control/perhaps get rid of just a thought

Mountain Ash

The are devouring the tree, will they kill it?

Variation on Fruit Cocktail attractant for Japanese Beetles

A simpler and cheaper alternative to the Fruit Cocktail attractant is Apple Cider Vinegar, dishwashing detergent, and sugar. I use about a cup of vinegar, a spoonful of sugar, and a few drops of detergent in a large open can. The fruity vinegar and the sugar attract them and they drown in the soapy water. No waiting for fermentation and there's only one container.

Japanese Beetle

Does the vinegar mixture get mixed into the water? Or put the mixture into a can to sit in the water?

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