Of all the different pests that can destroy gardens, the Japanese beetle is one of the most destructive.
This pest was first introduced to the United States in the early twentieth century from Japan, and its numbers began to explode after the banning of DDT in 1972. Each spring and summer, this green, blue, and copper-colored insect devours plants, flowers, crops, and shrubbery across the Eastern United States.
Getting rid of Japanese beetles can be difficult because this pest is an invasive species that multiplies rapidly and spreads quickly in the warmer months. But with the right products and approach, Japanese beetles can be controlled each year.
In this guide, you’ll learn:
- What attracts Japanese beetles to your yard
- What to do if Japanese beetles get into your home
- What chemical and natural remedies can get rid of Japanese beetles
- Prevention techniques to take against Japanese beetles
- The best products overall to get rid of Japanese beetles
Keep on reading and we’ll walk you through everything you need to know! But if you’re short on time, click here to jump to our suggestions for getting rid of Japanese beetles.
If trying to exterminate Japanese beetles on your own becomes too challenging, we recommend Orkin, Terminix, and Aptive. These exterminators have some of the best trained professionals that are able to use traps, baits, and other chemically treated solutions that are often more effective than standard DIY methods.
Ed has been working in the pest control industry for years helping 1,000's of homeowners navigate the world of insect and rodent management. He manages Pest Strategies now helping homeowners around the world!
Table of Contents
What Attracts Japanese Beetles To Your Yard?
In the pest control community, we sometimes refer to the Japanese beetle as a ‘free agent’ pest; this insect will eat any type of foliage and multiply quicker than it can be destroyed. A female Japanese beetle can lay upwards of 40-60 eggs in her lifetime, and this pest is attracted to over 300 different species of plants in the United States.
Japanese beetles start out as grubs underground through the autumn and winter months and emerge as adults in the spring. Once emerged, an adult lives for roughly 4-6 weeks and consumes massive amounts of foliage in this small span of time.
This pest prefers warm and moist environments, so the Eastern and Southeastern United States is the largest region for Japanese beetle activity. The insects will swarm around a region and settle in places that offer plenty of plants and shrubbery for feeding. With such a large flavor palette, virtually any yard or garden is attractive to this pest.
How to Identify Japanese Beetles
Adult Japanese beetles are oval-shaped and about ½ inch in length. The outer wing shell is copper-colored and the head is typically green or blue if viewed from a distance.
Six-to eight patches of white hair clusters line the rim of the abdomen. It isn’t hard to identify this beetle, and most beetles will feed on plants out in the open with no fear.
Another way to identify this pest is to check for leaf-shredding on your plants. This beetle prefers to feed on the outer parts of foliage instead of the root. Leaves will appear skeletonized which is from the beetle chewing away from the exterior of the leaf leaving a veiny, hollowed look to the plant.
It’s not just adults that you have to worry about, Japanese beetle grubs will feed off the roots of plants underground before becoming adults in the spring. This is why Japanese beetle pest control needs to target both adults and the grubs.
Read More: How to Kill and Get Rid of Carpet Beetles
Do Japanese Beetles Get Inside The Home?
This pest needs soil to reproduce effectively, but if outdoor populations are crowded, the beetles can fly indoors and begin feeding on houseplants inside the home.
If you have no indoor plants, the beetles will not stick around inside. Any beetles that you see can be removed with a pair of gloves and destroyed.
If you are noticing large amounts of beetles in the home, this could be a carpet beetle infestation, which you can read more about here.
Pesticides work quickly to kill Japanese beetles.
Pyrethrins are highly effective against this pest and pose less of a danger to pollinators like bees than other insecticides. It does no good to kill pollinating insects, therefore, avoiding the petal of flowers is best when using insecticides to treat Japanese beetles.
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What Natural Remedies Will Get Rid of Japanese Beetles?
If there are some natural alternatives to pesticides that work, this is always a good option to consider before insecticides. With Japanese beetles, there are a few natural treatments you can choose from.
Diatomaceous Earth is one of the best methods to use for covering a wide area in your yard with an effective treatment. DE powder is made from tiny, crystal-like fossils called diatoms. These fossilized shells are made of silica that has microscopic, razor-sharp edges that can rip the waxy outer shell of insects.
This product is great because insects are unable to develop a resistance to the sharp edges of the shells. Furthermore, DE powder also works by acting as a desiccant (drying agent) when insects walk through it. Once the powder attaches to a beetle’s body, the insect essentially dies from dehydration in as little as 24 hours.
Diatomaceous Earth will not harm plants and the product will not deactivate once it is wet. However, strong thunderstorms and heavy downpours can wash the powder away.
To apply DE powder, put on a pair of latex gloves to prevent your skin from drying and spread the powder on all plants and shrubbery. Since this product is not as effective if clumped, it is best to use a dust applicator to spread as thin a layer as possible to avoid the beetles from simply flying around it.
Food grade Diatomaceous Earth is generally safe around pets or children. But it is always a good idea to monitor their activity when outside near the powder. DE powder is evergreen as a residual; even if the product gets wet, it will work again once it dries out as long as it isn’t washed away.
Read more: Diatomaceous Earth
The Neem tree is found in Asia and the oil extracted from the tree is one of nature’s naturally occurring pesticides. It is a yellowish-brown color with a slightly bitter taste, and a garlic or sulfurous smell to it.
Neem oil interferes with the hormone system in insects, making it difficult for them to reproduce. It also reduces their feeding and acts as a repellent, pushing insects away from areas treated with it.
Neem oil is readily available as a spray application for plants and other foliage. The spray should be applied to plants every 7 to 14 days and you should notice a major reduction in Japanese beetles over this time period.
One drawback to using neem oil is that Japanese beetles may move to other foliage in your yard that is not covered with the oil. So this means you would have to buy a large supply of neem oil to cover all outdoor plants and shrubs.
Neem oil is completely organic and is safe to use around pets and kids.
Read more: Neem oil facts
Another natural method for getting rid of Japanese beetles is to use geraniums as a toxic agent near Japanese beetle colonies.
Since Japanese beetles will eat virtually any type of foliage, research has proven that geraniums cause toxicity in Japanese beetles. Geraniums poison the system of Japanese beetles that can lead to temporary paralysis or death after ingestion.
If the beetles become paralyzed after tasting geraniums, you can easily pick them away and dispose of them. What’s even better is that you can either grow geraniums in your yard or use a spray application of geranium oil to fight against the beetles. Let’s take a look at each method.
- Geranium seeds. Growing geraniums is best-suited in areas around plants that you do not want Japanese beetles feeding upon. This will kill beetles, but like neem oil, there is the possibility of the beetles simply avoiding the plants if they survive tasting them and moving on to other plants in the area.
- Geranium oil. The better method overall is to use geranium oil as a contact spray application. You can mix 12 drops of this oil in one cup of water and spray the leaves of plants. Chances are that Japanese beetles will be repelled by the smell of the oil before even attempting to take a bite out of the plant.
All of the above natural products work great for killing adult Japanese beetles, but what about the underground grubs? For this, using beneficial nematodes is a great way to allow a natural hunter/prey relationship to play out.
Beneficial nematodes are tiny, microscopic worms that literally hunt over 200 pests and attack the pest much like piranhas in the wild.
This attack on grubs is to release bacteria into the grub’s bloodstream. The bacteria multiply and eventually kill the grubs. The nematodes then feed on the dead grub until it is gone. After that, they go off in search of more grubs.
Beneficial nematodes are easy-to-use. Simply open the package, dump the nematodes into a bucket of water or inside of a garden sprayer, let the nematodes soak for one minute, and then spray over all of the soil where Japanese beetles feed on plants.
Be sure to use beneficial nematodes within 30 days of purchase and always check the expiration date on the package to ensure freshness. Beneficial nematodes need moisture to survive so apply them after it rains or make sure you irrigate the soil before releasing the nematodes.
Irrigate the soil at least every seven days if you live in a dry region.
Read more: Nematodes for flea control
All of these methods are organic, and even though these products may not kill the beetles on contact, they are safe and easy-to-use.
What Pesticides Will Get Rid Of Japanese Beetles?
Fighting against Japanese beetles can be a chore, so it is good to have a firm grasp on what products work and what to stay away from. Natural remedies are great for the environment but let’s face it, these alternatives do not always work or take a bit too long.
Pesticides work quickly to kill Japanese beetles. Pyrethrins are highly effective against this pest and pose less of a danger to pollinators like bees than other insecticides. It does no good to kill pollinating insects, therefore, avoiding the petal of flowers is best when using insecticides to treat Japanese beetles.
With those dangers in mind, here are four effective and low-toxicity pesticides to use against this pest.
This garden insect spray by Bonide contains the chemical pyrethrin, which is a central nervous system antagonist when absorbed by insects. There is a sharp divide in the pest control community when it comes to the efficacy of pyrethroid insecticides due to insect resistance.
This all depends on the resistance development in each specific pest. Outdoor pests do not receive nearly as much saturation and exposure to pyrethroids as interior pests. Therefore, chemicals like pyrethrin do not develop as much resistance as a pest like bed bugs.
What’s great about Bonide Garden Insect Spray is the formulation that prevents residue on plants and flowers. This can be unattractive for many gardeners, especially when used on ornamentals.
To use against Japanese beetles, mix three tablespoons of product per one gallon of water, a gallon garden sprayer is ideal. Spray all outdoor plants liberally with the mixture but not to the point of run-off.
The only drawback to this product is the lack of a strong residual component; you will need to spray plants again after 2-3 days.
If Diatomaceous Earth is not doing the trick, Delta Dust is a great alternative that uses a chemical compound called deltamethrin to destroy Japanese beetles.
Deltamethrin also attacks the central nervous system of insects and has better resistance to moisture than DE powder.
Like any dust pesticide, Delta Dust should be applied inside of a dust applicator. Insects will avoid large clumps of the powder, and the clumping of the product could also lose its effectiveness. Apply a light dusting of the product to leaves of plants no thicker than the appearance of steam or smoke.
Temprid FX is an outstanding pesticide, and one of the only insecticides along with Crossfire that can actively destroy bed bugs, which is a big deal. With that said, this product is also incredibly potent and should be used with the utmost caution.
Temprid FX’s two primary chemicals are imidacloprid and b-cyfluthrin. Both of these pesticides attack the central nervous system of insects, with b-cyfluthrin being in the less potent family of pesticides called pyrethroids.
The b-cyfluthrin in Temprid FX acts to poison the digestive system of insects by causing constant muscle spasms that eventually leads to paralysis or starvation.
The imidacloprid is far more toxic and also causes paralysis and eventually death at a much quicker rate than b-cyfluthrin alone. When combined in Temprid FX, Japanese beetles have a double dose of central nervous system attacks and will usually die within minutes of exposure.
Additionally, imidacloprid is absorbed into the leaves of plants through a strong residual effect, which means Japanese beetles will ingest the poison up to eight weeks after the initial application.
If beneficial nematodes are not working fast enough to destroy grubs, a product like Scott’s Grub X1 may be the answer.
This product is a soil treatment that can cover up to 10,000 square feet of yard coverage. The active ingredient is chlorantraniliprole, an insecticide that consistently reduces white grubs in the ground by up to 65%. It isn’t as water-soluble as some other insecticides so you’ll have to mix it vigorously.
Scott’s Grub X1 comes in the form of granules, so you will need to use a spreader to effectively cover large areas of soil across your yard. It’s best to cover the entire yard to ensure you are applying the chemical to any possible hot spot for Japanese beetle grubs.
Apply this product to the soil at the end of the Japanese beetle season in early autumn. This will make sure that all grubs are killed and will not emerge as adults the following spring.
What Can Prevent Japanese Beetles In The First Place?
To prevent Japanese beetles, it’s important to remember that the egg to adult life cycle occurs under the soil. Using a product like Scott’s Grub X1 in late summer and early autumn is a great way to destroy grubs before they molt into adults in early spring.
If you work to destroy the life cycle, you destroy the population. This will not prevent roaming Japanese beetles from scouting your yard for feeding and mating spots. If you destroy an underground colony of grubs and see stray Japanese beetles in your yard, use one of the spray applications we mentioned for contact killing as needed.
Japanese beetles are outdoor pests that cause widespread damage to plants and crops each year. If you ever see these insects in your yard, it is imperative to treat the soil immediately to destroy the life cycle that is certain to be present.
Thankfully, there is very little resistance to pesticides with this pest, and there are numerous natural remedies that you can use to eradicate them. Your plants, flowers, or crops cannot survive a Japanese beetle invasion, so be sure to treat your yard to prevent this invasive species from taking it over.