How To Get Rid Of Japanese Beetles

Japanese beetles are metallic green or bronze insects roughly half an inch long with copper-colored wings. The sides of their abdomens each have five patches of white hair, while the tips have two patches of white hair. True to their name, the insects are native to Japan and arrived in North America in 1916. Though they can be found across the United States, they’re especially prominent in the states east of the Mississippi River.

Known for starting at the top of plants and working their way down, the bugs have a preference for roses, perennial hibiscus, raspberry bushes, sassafras, hollyhocks, Norway maple, black walnut, gray birch and American elm. Japanese beetles also notoriously love fruit trees, favoring pear, plum, peach and cherry trees the most. That said, if their favorite plants aren’t around, they’ll eat pretty much anything.

The Japanese beetle is a damaging insect that feeds on over 300 species of plants in both turf and crops. This pest is relatively easy to identify due to its metallic blue-green heads, copper-colored backs and small white hairs lining each side of the abdomen. They usually feed in groups, so if you see one, be sure to look around for others.

Japanese beetles are known for their year-round damage to roses, beans and many other popular garden plants. Therefore, their damage is easy to spot. The larvae chew the leaves and stems of the plant while the adult beetles feast on the foliage and flowers. So, skeletonized leaves and flowers are a significant sign that Japanese beetles are present.

Japanese beetles are also a threat to lawns. They will eat the grass from underneath, leaving it sparse and yellowed; in severe cases, it can cause small bare spots. Their presence can result in reduced plant function, stunted growth and diminished plant health.

Japanese beetles have a great sense of smell. It’s likely that the scent of your plants and trees attracted them to your lawn. Moreover, the smell of a plant that has been bitten by a Japanese beetle attracts even more Japanese beetles, leading to a behavior called “group feeding” that can seriously devastate trees and other plants.

Additionally, female Japanese beetles lay eggs in soil, and the offspring hatch into larvae known as grubs. Grubs will feed on the roots of vegetable plants and turfgrass, thriving especially on the sorts of high-quality turfgrass found on golf-courses and lawns. So next time you tee up and notice removable patches of grass beneath your golf club, know that Japanese beetles are probably to blame.

1. Nip It in the Bud

Japanese beetles are especially attracted to the smell of rotting and diseased fruit, so be sure to keep a close eye on your garden and discard anything past its prime or in questionable health. That way, you can dramatically decrease your chances of having a serious infestation.

2. Get on Your Soap-Box

Though simple, a mixture of soap and water is pretty effective at eliminating Japanese beetles. In a spray bottle, mix a quart of water with a teaspoon of dish soap, and spray any plants that appear to be infested. The soap will suffocate the insects, and they’ll fall right off your vegetation.

3. Try a Hands-On Method

One effective—albeit icky—way to get rid of Japanese beetles is to pick them off your plants by hand. The insects don’t sting or bite, so if you have a manageable number of them in your yard, you can just grab them and throw them directly into a bucket of soapy water to ensure they suffocate. Wear gloves if you’d like.

4. Don’t Forget This Dead-On Solution

The scent of dead Japanese beetles repels living Japanese beetles. Place your collection of stiffs in a container near your plants in order to deter the other guys from achieving a similar fate.

5. Be a Neem-Dropper

Neem oil is a natural pesticide found in neem trees. When Japanese beetles consume neem, they pass it onto their eggs, killing the hatched larvae before they mature into adulthood. And since neem is nontoxic, you can spray it directly on your plants.

6. Skewer Them

Japanese beetles lay eggs in soil, and by early fall, the grubs will be feeding on your lawn or garden’s roots. Though lawn aerator shoes are notoriously effective at their intended purpose, you can use them to skewer grubs by strapping them on and walking around your lawn. The spikes are the right length to effectively kill off larvae. So if you have an old pair of aerator shoes sitting idly somewhere in your garage, break them out and give them a second life.

7. Welcome the Birds

Many species of bird—like catbirds, cardinals and robins—eat beetles. Starlings and crows will eat the grubs. For a natural remedy to your Japanese beetle infestation, welcome birds into your yard by providing them with food, shelter and water.

8. Bring on the Flies

It might seem crazy to supplement your beetle infestation with even more insects, but tachinid flies can prove very effective at getting rid of Japanese beetles. They are drawn to large groups of Japanese beetles and lay eggs on their heads, which kills them. Tachinid flies feed on nectar and favor flowers like fennel, dill, mint, sweet clover and gomphrena. So if you plant those around your garden, you’re likely to eliminate your Japanese beetle infestation.

9. Cover Up

A row cover is a spun-bonded or woven cover made of plastic, polyester or polypropylene. It can be placed over plants and crops to prevent pest attacks while still being permeable to sunlight, water and air. Place row covers over your plants, and rest assured that Japanese beetles won’t get to them as they continue to grow.

Japanese beetles are a major backyard pest that can completely devastate your plants. Unfortunately, there’s very little you can do to keep them from damaging your yard or eating everything in sight. However, you can prevent the infestations from becoming problematic by doing a few simple things.

Plant Selection

The right plant selection can help you control Japanese beetles, such as conifers, trees and shrubs, as well as annuals and perennials with thick foliage or woody stems. 

Eliminate Grubs

Get rid of grubs fast when they’re in their larval stage, otherwise known as wigglers. In late spring and fall (beetles have two life cycles per season), spray the lawn with two tablespoons of liquid dishwashing soap diluted in 1 gallon of water per 1,000 square feet.

Introduce Milky Spores

Introduce the fungal disease milky spore into your lawn to control the Japanese beetle larvae population. This fungal disease is safe and easy to apply, and it’s 100% natural, so you don’t have to worry about harmful chemicals or pesticides.

Beneficial Nematodes

Control Japanese Beetle larvae in your lawn using parasitic nematodes. This treatment must be applied when the grubs are young and require abundant irrigation during and following application. 

Companion Plants

Companion planting is a relatively simple strategy for keeping pests away from your garden. If there are plants nearby that the Japanese beetle does not like, you can plant them as a buffer to protect your crops. Garlic, tansy and rue have strong scents that repel Japanese beetles and other pests.

Parisitic Wasps

Attract insects that help control the Japanese beetle population by planting nectar-rich flowers, like asters, goldenrod and butterfly weed. 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.