Are Japanese beetles treating your garden like an all-you-can-eat buffet? You aren’t alone. Every year, thousands of homeowners have to figure out how to get rid of Japanese beetles and their grubs.
After Japanese beetle grubs destroy your lawn, they’ll grow into adults who quickly devour all your plants. We’re here to help you save your landscape by exterminating Japanese beetles and preventing them from coming back next year.
- 10 ways to get rid of Japanese beetles
- How to prevent Japanese beetles
- How to identify Japanese beetles
- FAQ about Japanese beetles
- Don’t let Japanese beetles take over your lawn and garden
10 ways to get rid of Japanese beetles
Here are several methods you can try to get rid of adult Japanese beetles once they emerge in summer. Fortunately for your plants and the environment, most of the best ways to exterminate Japanese beetles are organic and chemical-free.
Note: If you’re dealing with the grub stage of Japanese beetles in your lawn right now, see our guide How to Get Rid of Grubs in Your Lawn.
The best way to get rid of Japanese beetles also happens to be the simplest way: Picking the beetles off your plants by hand. The job might be tedious and a little icky for some people, but the trouble is worth how well this method works!
How to hand-pick Japanese beetles: Look for the adult beetles on or near damaged plants in your garden. Pick each beetle up one by one and immediately drop them into a bucket of soapy water.
When to look for Japanese beetles: Adults are most active during the early morning or late afternoon, so those are the best times of day to go beetle hunting. If you have a large beetle population, you may want to pick them off twice a day until the herd thins out.
Pro tip: After hand-picking beetles, you can feed them to pet chickens or large fish as a treat.
2. Neem oil spray
Before you use neem oil to get rid of Japanese beetles, you have to understand the difference between the two kinds of neem oil:
- Neem oil with azadirachtin: When beetles ingest azadirachtin, they pass the toxic chemical on to their larvae, and the larvae die before reaching maturity. In some states, this type of neem oil is only available for professional use.
- Clarified hydrophobic neem oil: This is the neem oil usually sold at garden centers, and it doesn’t contain azadirachtin. This type isn’t effective against adult Japanese beetles, but it can drown the larvae (grubs) if you catch them while they’re still young.
How to use neem oil for Japanese beetles: If you can get your hands on neem oil with azadirachtin, spray your plants with it. When the beetles eat your plants, the chemical will go to work. You’ll have to spray the plants again after rain for this treatment to remain effective.
WARNING: Neem oil can harm beneficial insects and your plants, so use it with caution. Don’t use neem oil if you live near a natural body of water, as it can harm aquatic life.
3. Homemade insecticide
You can easily make an insecticide for Japanese beetles using ingredients you probably already have around the house. Here’s what you’ll need:
- 1 quart water
- 1 teaspoon liquid dish soap
- 1 cup vegetable oil
- 1 cup rubbing alcohol
Combine all the ingredients above and shake well. Pour the solution into a spray bottle and spray your plants with it every 10 days.
WARNING: This spray can hurt some plants. If you notice leaves beginning to wilt, rinse them with clean water and discontinue use of the spray.
4. Dead beetles as repellent
Have you ever heard a story about a king mounting his enemies’ heads on spikes to ward off would-be attackers? You can do something similar for Japanese beetles.
Beetles (and all insects) give off a “death stench” when they die. The stench acts as a warning to other members of their species to stay away from potential danger. Take advantage of the death stench to keep Japanese beetles out of your garden.
After a few rounds of hand-picking, trapping, or spraying, you should have quite a few dead beetles on your hands. Collect the dead beetles in containers and leave them around your garden. The smell will encourage any remaining beetles to leave and keep new beetles from moving in.
5. Drop cloth
In the evening, lay a drop cloth on the ground surrounding plants affected by Japanese beetles. Check again in the morning, during the beetles’ active period, and the cloth should be crawling with them.
Now, all you have to do to get rid of the beetles is pick up the cloth and shake them off into a bucket of soapy water. Repeat the process every day until you no longer find beetles on the cloth in the morning.
6. Attract predators and parasites
Japanese beetles have many natural enemies that can keep the population under control for you. If you have a Japanese beetle problem, you want as many of those natural enemies in your yard as possible.
Birds are a major predator of the Japanese beetle. Some birds eat the grubs, while others prefer the adults. Either way, the birds are on your side. Here’s how you can attract birds to your yard:
- Set up birdhouses around your garden
- Set up a birdbath or two and keep the water clean
- Install bird feeders near where the beetles are located
The Tachinid fly is a parasitic fly that destroys adult and larval Japanese beetles. Tachinid flies show up on their own wherever there are lots of Japanese beetles. You can attract more flies and encourage them to stay in your garden by planting their favorite plants to eat, such as:
- Herbs in the dill family
- Flowers in the aster family
7. Plant geraniums as a natural pesticide
Japanese beetles love to eat geranium blossoms, but the natural chemicals in geraniums paralyze them. After the beetles fall to the ground and can’t move, either predators will eat them or you can find them and pick them up yourself.
Plant geraniums close to the plants you want to protect from Japanese beetles so they eat the geraniums instead of the rest of your garden.
8. Bait plants
With bait plants, you sacrifice one or a few plants to save the rest of your garden. The concept is simple: Choose plants that are especially attractive to beetles and plant them in a bed far away from the rest of your garden.
The goal is for beetles to swarm the bait plants and leave your other plants alone. Once all or most of the beetles have moved to the bait plants, you can easily remove them by hand or with a bug vacuum.
Here are some plants that Japanese beetles love that should work well as baits:
- Roses (Rosa spp.)
- Grapes (Vitis spp.)
- Hibiscus (Hibiscus spp.)
- Red raspberry (Rubus idaeus)
- Sunflower (Helianthus spp.)
WARNING: Bait plants may not work if you have a small yard. If the bait plants are too close to the rest of your garden, Japanese beetles will get into your garden and the bait plants, defeating the whole purpose.
9. Japanese beetle traps
Japanese beetle traps use a lure (pheromones, floral scents, or both) to attract beetles from far and wide. The beetles fly into the trap, then get stuck in a bag or funnel, depending on the trap’s design.
The problem with Japanese beetle traps: These traps are usually better at attracting beetles than trapping them. Because of the strong-scented lure, all nearby beetles will swarm to your yard, and the trap will only catch about 75% of them. You might end up with more beetles than you had before.
However, traps can be effective if your property is several acres. In that case, set up traps around the perimeter of your yard, as far away as possible from plants you want to protect. The trap will still attract lots of beetles, but at least they won’t be near your garden.
10. Chemical insecticides
Unnatural chemical pesticides should always be a last resort to use in the lawn and garden. They harm pollinators and other beneficial insects, and they often end up polluting water sources.
But if you’ve tried every natural solution in the book and Japanese beetles persist in your lawn, it might be time to turn to chemicals.
First, try low-risk pesticides with low toxicity to humans and beneficial insects, such as:
- Neem oil
- Bacillus thuringiensis (Bt)
For a more long-lasting effect, use residual pesticides on your plants. These stay on the plant and remain effective for weeks, which means they affect more beetles. Some residual pesticides that work on Japanese beetles are:
- Chlorantraniliprole (Acelepryn®): Lasts two to four weeks
- Pyrethroids (including bifenthrin, cyfluthrin, lambda cyhalothrin, and permethrin): Lasts two to three weeks
- Carbaryl or acephate: Lasts one to two weeks
Another option is systemic insecticides. With systemic insecticides, you drench the soil so that plants soak in the chemicals through their roots. Then, anything that eats the plant will be poisoned. These are not recommended since they also may harm beneficial insects.
Some examples of systemic insecticides for Japanese beetles:
Follow label instructions: When using any insecticide, follow the instructions on the product label. The label should tell you how much product to use and how to apply it.
How to prevent Japanese beetles
The best thing for your garden would be to prevent Japanese beetles before they ever get ahold of your plants.
Here are the most effective methods for preventing Japanese beetles:
- Exterminate grubs before they grow into beetles.
- Let your lawn dry out in summer so beetle eggs can’t survive.
- Cover your plants with row covers to block beetles from touching them.
- Choose plants that don’t attract Japanese beetles and hopefully they’ll stay away from your garden on their own.
- Make natural Japanese beetle-repelling sprays and apply them to your plants every few days.
Want more details on how to keep these destructive pests away? We cover all these prevention methods in greater detail in How to Prevent Japanese Beetles.
How to identify Japanese beetles
How can you tell if Japanese beetles are the culprits behind your lawn and garden’s problems? Look for these identifying features of a Japanese beetle infestation.
What are Japanese beetles?
The Japanese beetle (Popillia japonica) is an invasive species of scarab beetle originally from Japan. Japanese beetles first appeared in the United States in the early 1900s, and they’ve since grown into one of the most common lawn and garden pests in the country.
Japanese beetles cause problems at all stages of their life cycle. The young larvae, also known as grubs, feed on grass roots and turn lawns brown. The adult beetles eat the leaves and flowers of more than 300 types of plants.
What Japanese beetles look like
The best way to be sure you’re dealing with Japanese beetles is to see them yourself. Here’s what to look for.
Adult Japanese beetles:
- About ½ inch long
- Metallic green head
- Coppery wings
- White hairs along both sides of the body
- About 1 inch long
- Milky white body and brown head
- Look like C-shaped worms with tiny legs near their heads
Signs of Japanese beetle damage
It’s usually easy to diagnose a Japanese beetle problem because the damage they cause is distinct.
Adult Japanese beetle damage: Adult Japanese beetles leave only the veins of a leaf behind when they eat leaf tissue, and the result is a sort of “skeleton” of a leaf. The damage resembles a lacy pattern.
Grub damage: Japanese beetle grubs feed on the roots of grasses and garden plants, which leads to brown patches of grass and dead plants. Affected grass and plants will pull up from the soil easily because the roots are damaged and weak.
When Japanese beetles are active
Luckily for gardeners everywhere, Japanese beetles aren’t a 24/7/365 pest. You can expect them at certain times of the year and day.
What time of year are Japanese beetles active?
- Spring: Grubs emerge from deep underground in spring. Look for browning patches of lawn at this time.
- June-August: Adult beetles usually emerge from the soil in late June, but they can be active as early as mid-May in the South. The adults live for 40 days, during which they lay eggs and feed on plants. The last adult beetles will die out by late August or early September.
- Early fall: After the adult beetles lay their eggs in summer, the year’s second generation of grubs will begin to feed on grass roots in early fall.
What time of day are Japanese beetles active?
- Early morning and late afternoon: Adult Japanese beetles might feed at any time of day, but they’re usually most active during the early morning and late afternoon.
- All day for grubs: Grubs don’t have a particular feeding time, and you might find them active at any time of day. They live in the soil, so they aren’t easy to spot. You’ll probably have to dig up some of your soil to find them underground.
Japanese beetle behaviors
Feeding: Japanese beetles feed in groups, so you’ll rarely find one on its own. If you do see one alone, it’s safe to assume others are nearby.
Pheromones: When beetles eat a plant, the plant begins to release a particular odor that attracts other beetles to the food source. For this reason, a handful of Japanese beetles can turn into an infestation quickly.
Foraging: Japanese beetles will travel several miles in search of food. So, even if you don’t have grubs in your lawn in spring, you could end up with an infestation of adult beetles from somewhere else in summer.
FAQ about Japanese beetles
Here’s what to do when Japanese beetles appear on your rose bushes:
—Nip the buds (because they bloom too quickly for insecticides to be effective)
—Spray the leaves with an insecticide or repellent spray
—Continue until the beetles become scarce
Once you’ve handled the beetle infestation, you can allow your roses to bloom like normal again. Sacrificing a few blooms is better than a whole season of holey, chewed-up roses!
Yes. For healthy plants, Japanese beetles usually only cause cosmetic injury. Most plants should bounce back just fine.
Some plants are more vulnerable to damage and could potentially die from severe Japanese beetle feeding. Examples include young plants, plants with other health problems, some fruits, some vegetables, and some herbs.
Japanese beetles are found throughout the Midwestern and Eastern United States. They’re most common East of the Mississippi River.
No, Japanese beetles don’t bite or otherwise harm humans or animals. So, you don’t have to be afraid of picking them off your plants by hand!
Japanese beetles will go away during winter. However, more grubs will probably show up in spring. If you want them to go away permanently, you have to break the cycle by taking out all or most of a generation of adults or grubs.
Don’t let Japanese beetles take over your lawn and garden
Don’t get stuck in an endless cycle of grubs and adult Japanese beetles. The grubs can totally destroy your lawn if there are enough of them, and the adults can chew through most of your garden in the few weeks they are alive.
Japanese beetles will keep coming back year after year unless you do something to stop them. If you have an infestation in your yard now, knock it out ASAP using the methods described above. That’s how you beat the beetles for good.
Are DIY methods not cutting it for your Japanese beetle infestation? Call a pest control professional for help.
Main Photo Credit: MaineCoast | Pixabay