top of page
  • Writer's pictureKassi K.

How To Get Rid of Japanese Beetles in Your Garden

Updated: Aug 25, 2023

The Japanese beetle (Popillia japonica) is a highly recognizable and notorious insect species known for its striking metallic green and copper-colored exoskeleton. Native to Japan, this beetle is known for its invasive nature and destructive feeding habits. Since its accidental introduction to the United States in the early 20th century, the Japanese beetle has become a significant pest, causing extensive damage to a wide range of ornamental plants, fruits, vegetables, and agricultural crops. Today we will delve into the characteristics, life cycle, feeding habits, and management strategies related to the Japanese beetle.

Japanese beetle on leaf

Why Is the Japanese Beetle Harmful?

Many people marvel at this beautiful looking beetle, though many are unaware of its destructive tendencies. If you are wondering why is the Japanese beetle harmful, we have some answers for you. These pests are considered harmful due to their feeding habits and potential to cause significant damage to a wide range of plants and crops. Here are some specific reasons why the Japanese beetle is considered a pest and harmful to the environment.

Feeding Habits Cause Severe Plant Damage

Adult Japanese beetles feed on a variety of plants, including ornamental flowers, fruit trees, vegetables, and field crops. They are voracious feeders, consuming the tissue between the veins of leaves, resulting in the characteristic "skeletonized" appearance of the leaves of plants. In addition to the appearance of plants being affected, the feeding activity of Japanese beetles causes severe damage to plants, leading to reduced photosynthesis and stunted growth. This can weaken the overall health of plants and make them more susceptible to other stressors, diseases, and environmental factors. In agricultural settings, Japanese beetles can cause significant economic losses by damaging crops such as grapes, corn, soybeans, and various fruits, impacting both the quality and quantity of the harvest.

Japanese beetles feeling on leaves

Invasive Species

Japanese beetles are not native to North America. They were accidentally introduced in the early 20th century and have since become established in many parts of the continent. As an invasive species, the presence of Japanese beetles has the potential to disrupt local ecosystems by outcompeting native insects for food resources. This can affect the balance of the ecosystem and impact native plant and insect species.

Lifecycle Impact

Japanese beetles have an impact in more stages of life than just their adult phase. The larvae, also known as grubs, live in the soil and feed on plant roots. Their feeding can damage grass and turf, leading to brown patches in lawns. This can have economic and aesthetic consequences for homeowners and landscapers.

Resistance To Control Methods

Japanese beetles have shown the ability to develop resistance to certain insecticides over time, making their management more challenging.

Transmission Of Plant Diseases

The feeding activity of Japanese beetles creates wounds on plants that provide entry points for pathogens. Along with this, the compromised health of the plant can easily make it less capable of resisting other pests and diseases that may try to attack the plant.

What Does A Japanese Beetle Look Like?

Japanese beetle closeup

What does a Japanese beetle look like? They are distinctive insects with easily recognizable characteristics. Adult Japanese beetles are around half an inch long and are metallic green with coppery-brown wing covers, or elytra. This combination of colors gives them a shiny appearance. The wing covers have a series of small, white tufts of hair on each side. These white tufts form a pattern of dots that can be seen when the beetle is viewed from certain angles. The head of a Japanese beetle is a shiny metallic green, similar to the rest of its body. They have a pair of prominent white tufts of hair projecting backward from the sides of the head. The antennae are relatively short and end in a club-like shape. The legs of Japanese beetles are relatively long and appear black or metallic green. Japanese beetles have an oval and slightly flattened shape. When they're at rest, their elytra cover their wings, and they resemble a small turtle.

The combination of the metallic green coloration, white tufts of hair, and the coppery-brown elytra with the metallic green head makes the Japanese beetle quite distinct and easy to identify. Remember that the appearance of Japanese beetles can vary slightly, and they might sometimes appear more brownish or less shiny if they're older or have been exposed to environmental factors.

12 Tips On How to Get Rid of Japanese Beetle in Your Garden

Japanese beetles can be a nuisance and are not always easy to get rid of. If you are struggling with these pests in your lawns, landscapes, or gardens and are wondering how to get rid of Japanese beetle, here are some methods you can try to manage and control the population.

1. Handpicking

Go out in the early morning when the beetles are less active and handpick them off your plants. Drop them into a bucket of soapy water to kill them.

2. Prune Affected Areas

Remove heavily infested foliage and plants to reduce the attraction of beetles to your garden. This will not only get rid of beetles feeding on those parts of your plants, but it will also encourage your plants to put energy into new growth instead of trying to maintain damaged foliage.

Bonide Neem Oil Pest Control

3. Neem Oil

Neem oil is a natural insecticide that disrupts the beetles' feeding and reproduction. Follow the instructions on the bottle and spray it on the affected plants.

BeetleGONE! insect control

4. beetleGONE!

BeetleGONE! is the first Btg (Bacillus thuringiensis galleriae) bio-insecticide to control adult beetles at the same level of efficacy as other chemical products. This product, however, does not have the negative side effects of chemical options and does not harm other beneficial insects.

Grub Exterminator Beneficial Nematodes

5. Beneficial Nematodes

Beneficial nematodes are microscopic organisms that can be applied to your soil to target and kill Japanese beetle larvae. They are environmentally friendly and safe for other beneficial insects.

Bonide Insecticidal Super Soap Direct Spray

6. Insecticidal Soap

Insecticidal soaps can be used to directly spray on the beetles. These soaps suffocate the pests by disrupting their cell membranes.

Safer Brand EndALL Insect Killer Direct Spray

7. Pyrethrin-based Insecticides

Pyrethrin-based insecticides are derived from chrysanthemum flowers and can be effective against Japanese beetles. Always follow the instructions on the product label.

8. Introduce Natural Enemies

Paenibacillus popilliae (Milky spore disease) is a bacterial disease that affects Japanese beetle larvae. Applying milky spore powder to your lawn can help control the larval stage of the beetles. Istocheta aldrichi (Tachinid fly), are another enemy of the Japanene beetle. They lay their eggs on adult beetles, and their larva then tunnels into the beetle, killing it. Tiphia vernalis, a type of parasitic wasp, actually digs into the soil and lays their eggs on late-stage Japanese beetle grubs, killing them. Ovavesicula popilliae is a microsporidian (fungal) disease that also affects Japanese beetle larvae by infecting their tubules, causing reduced fecundity and reduced winter survival. Many of these are being used by government programs in an attempt to control and eradicate Japanese populations in Colorado and surrounding areas.

9. Rotate Plantings

Japanese beetles are attracted to specific plants, namely Hollyhock, Gaura, Rose of Sharon, crabapple trees, Japanese maples, Peking cotoneaster, beans, basil, raspberry bushes, grape vines, and more. Rotating the types of plants you grow in your garden can help disrupt their lifecycle and reduce infestations.

10. Maintain a Healthy Lawn

Regularly mow and maintain your lawn to discourage Japanese beetle larvae from developing in the soil. Applying insecticides to your lawn early in the season when Japanese beetles are in the larvae stage will kill the pests before they reach adulthood.

11. Companion Planting

Some plants, like garlic, chives, and catnip, can repel Japanese beetles. Consider planting these alongside more susceptible plants. Learn more about companion planting in our blog, "What Is Companion Gardening?"

12. Attract Predators

Birds, toads, spiders, assassin bugs, predatory stink bugs, and other beneficial insects can help control Japanese beetle populations. Provide habitats that encourage these predators to visit your garden.

How To Get Rid of Japanese Beetle

Japanese beetles can be difficult to get rid of, and there is not exactly one single method that is foolproof or gets rid of these pests permanently. Often it is best to combine several approaches for better results. Always be cautious and aware when using chemical pesticides, as they can harm beneficial insects and disrupt the ecosystem balance in your garden. Always read and follow the instructions on product labels and consider more environmentally friendly options whenever possible. If you have any questions or need help identifying pests in your lawn, landscaping, or garden beds, we are here to help! You can check out other blogs on common pests and diseases here, shop pest control products in our online store, or come into the Garden Center to speak to a professional.

43 views0 comments


bottom of page