How to Get Rid of Japanese Beetles

Written by Jennifer Gaeng
Published: December 16, 2021
Share on:

Advertisement


Japanese Beetle Popillia japonica isolated on a white background

Common signs of Japanese beetle infestation include brown areas of dead or dying grass and skeleton-like patterns on plant leaves.

©enterlinedesign/Shutterstock.com

Japanese beetles (Popillia japonica) were not a major concern in the US until around 1919, when they began invading North America, on imported ornamental plants. They have become a major annoyance to gardeners and farmers ever since. Why are so many people are looking to get rid of Japanese beetles?

Feeding on the roots of grass and other garden plants is what these insects do best. Asparagus, corn, soybeans, roses, bushes, and a variety of other ornamentals are favorites of the Japanese beetle. Infestations of Japanese beetle and their larvae are commonly characterized by brown patches of dead or dying grass and skeleton-like designs in the leaves of plants. In extreme cases, they can completely destroy a plant.

What Do Japanese Beetles Look Like?

Japanese beetle on leaf

Japanese beetles are 3/8″ long and 1/4″ wide, with metallic green bodies and copper wing coverings.

©iStock.com/PaulReevesPhotography

Japanese beetles measure three-eighths” in length and 1/4″ in width and have a metallic green hue and copper-colored wing covers. Apart from their eye-catching hues, they also have a polished surface, which gives them an awe-inspiring appearance.

Japanese beetles are not the only metallic, green, or copper beetles. To identify them, Japanese beetles have five white tufts under their wing coverings and another tuft at the end of their abdomen. Another sign of the Japanese beetle is damage. Japanese beetles leave skeletonized leaves or defoliate foliage in their wake.

Are Japanese Beetles A Problem?

While individual Japanese beetles aren’t particularly dangerous, these insects hatch in vast numbers and can swiftly defoliate a shrub, tree, or plant. Japanese Beetles appear in cycles: some years they’re practically nonexistent, while other years they’re all over the place. They are most active from late June until about September when the weather and climate cause them to die off. Adult Japanese beetles live for up to two months.

If there is a major infestation, many plants may be severely harmed or even killed. You may not be able to completely get rid of Japanese beetles because of their overwhelming numbers, but there are still ways to regulate and prevent them.

How to Get Rid of Japanese Beetles

Close up of a Japanese Beetle in nature against a blurred green background

A multi-step approach is the best way to get rid of Japanese Beetles. Trap plants, sprays, and covers are all examples of this.

©iStock.com/Cwieders

To get rid of Japanese Beetles, a multi-step strategy is the best option. Sprays, trap plants, and coverings are all examples of this. Keep reading to find out how to keep Japanese beetles at bay with these six tips.

Insecticide

For excessive amounts of Japanese beetles, a pyrethrin-based insecticide might be most effective. It can be used on plants, flowers, roses, trees, and shrubs to reduce pest populations.

Consider the fact that mature Japanese beetles are only around for a few weeks, so unless there is an extreme infestation, employing harsh insecticides isn’t necessary.

How to Get Rid of Japanese Beetles Naturally

As noted above, insecticides can be an extreme measure. There are also a number of natural alternatives for ridding a yard of Japanese beetles.

Neem Oil

Neem oil is a natural insecticide in neem seeds. It is golden to brown in color and smells like garlic/sulfur. It has been utilized for centuries for pests and disease control.

To get the most antifeedant effect, use neem oil as soon as possible after feeding has taken place. The Japanese beetle loses interest in feeding because of the reduced plant nourishment provided by this natural pesticide.

Trap Plants

A common trap plant is a geranium. Geraniums contain a chemical that temporarily paralyzes Japanese beetles, rendering them vulnerable to predators.

Trap plants are not like beetle traps. With beetle traps, a flowery aroma and beetle pheromones attract pests, which are then killed by an interwoven insecticide. While the amount they catch is impressive, these devices attract more Japanese beetles than they catch!

Soapy Solution

Japanese beetles can be suffocated by water and dish soap. Simply mix a quart of water with a teaspoon of dish soap. Any brand of dish soap will do. From here you have two options:

Spray

Pour the soapy water into a spray bottle, then spray the beetles on your afflicted plants. The beetles may fall from the plant and become prey for predators like birds.

Hand Pick

You can pick the beetles from the plant and drop them in a bucket of the water-soap solution. After you’re done, simply empty the bucket. Hand eradication is nothing to fear; Japanese beetles are slow-moving and do not bite or pinch, so they are easily removed. You can even wear a pair of thin gloves if you prefer.

Row Covers

A row cover may be the best way to prevent a Japanese beetle invasion. Row covers protect plants from Japanese beetles while allowing light and moisture so plants can continue to develop.

Row coverings work best from mid-June to mid-August when the beetles are feeding heavily. It can be used on shrubs, trees, flowers, decorative plants, and garden vegetables.

Plants Japanese Beetles Infest

Invasive Japanese beetles eating string bean leaves in a garden.

Japanese beetles do most of their damage from late June to September.

©Renman1605/Shutterstock.com

Although Japanese beetles feed on over three hundred plant species, some are more tempting than others! What plants should you grow to resist Japanese beetles?

10 Plants Japanese Beetles Are Most Attracted To:

  • Pin oak
  • Roses
  • American linden
  • Apple
  • Raspberry
  • Grapevines
  • Hibiscus
  • Japanese maple
  • Norway maple
  • Birch

10 Plants Japanese Beetles Are Least Attracted To:

  • Fir
  • Forsythia
  • Hemlock
  • Holly
  • Lilac
  • Magnolia
  • Ash
  • Boxwood
  • Burning bush
  • Clematis

Keep in mind that although Japanese beetles are less likely to attack these plants, there is no assurance that they won’t if there aren’t enough food sources around.

The photo featured at the top of this post is © Renman1605/Shutterstock.com


Share on:
About the Author

Jennifer Gaeng is a writer at A-Z-Animals focused on animals, lakes, and fishing. With over 15 years of collective experience in writing and researching, Jennifer has honed her skills in various niches, including nature, animals, family care, and self-care. Hailing from Missouri, Jennifer finds inspiration in spending quality time with her loved ones. Her creative spirit extends beyond her writing endeavors, as she finds joy in the art of drawing and immersing herself in the beauty of nature.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.