how to prevent Japanese beetles: Signs + 11 Quick Fixes

Growing plants in your home or having a home garden means dealing with annoying insects and pests. Read here to know how to prevent Japanese beetles and early signs of Japanese beetle infestation.

With summer’s fun-loving activities come the pesky pests that may ruin your garden. While you want to enjoy a picnic outdoors, Japanese beetle just might join in and destroy your garden.

If you have a home garden or even grow houseplants, you will know how exhausting it can be to get rid of Japanese beetles that are sitting feasting on your plants.

This blog will cover identifying and tackling a Japanese beetle pest infestation in your garden and returning your lush greens!

Understanding Japanese Beetles: Identification and Habits

The damage done by Japanese beetles is a lot. You can easily identify these pesky insects by their green and golden coloring with tiny white spots.

These insects are not very big in size. Just an inch long with wings neatly tucked away. You can notice the first few signs of Japanese beetles in late June or early July.

If you step out on a sunny day and find your plants damaged, chances are the Japanese beetle got to it! You can see the signs as the Japanese beetles leave behind holes in the plants or with frayed edges.

Japanese beetles survive as larvae underground in the fall and spring, feeding on the roots of plants or grass. Once summer hits, they rise to the surface and start their way to your plants!

It is ideal for controlling their infestation in time before it is too late. Japanese beetles can cause a significant amount of harm to your plants that’s why you must keep an eye out for them!

You can notice the early signs of damaged leaves or the insects crawling around throughout the day.

The Damage Caused by Japanese Beetles: How to Spot the Signs

Your houseplants are prone to serious damage if the Japanese beetles get to them, so you should recognize the early warning signs to control the infestation.

Damage Caused by Japanese Beetles:
  • Skeletonizing: One of the most obvious signs of Japanese beetle infestation is skeletonization, in which the insect eats through the leaf tissues and between the veins, leaving the frame of the leaf behind.
  • Missing petals: The affected leaves would also come with a lacy look due to Japanese beetle infestation and missing petals.
  • Flowers nibbled: The other warning indicator of the Japanese beetle is that the flowers and buds in your garden seem to be nibbled on or are somehow damaged. If the issue persists, it can even lead to slowed growth of the plant.
  • Brown spots: Another major indicator is brown spots appearing on the plant. The larvae might have gotten to the roots of your plant from the inside.
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If you notice any of these signs on your houseplants or home garden, you must act immediately before your entire garden is affected!

Biological Control Methods for Japanese Beetles

You can easily control the Japanese beetle infestation by using their natural enemies as part of a biological control strategy.

  • You can use parasitic nematodes, which are tiny worms, are an efficient control approach since they can target and destroy Japanese beetle larvae in the soil before they even surface.
  • The easy way to get these parasitic nematodes to the infected area is by using a watering can or a hose-end sprayer to directly water them on the plant’s roots.
  • Another approach you might want to consider is the milky spore disease, a bacterial illness that targets Japanese beetles and their larvae.
  • Other animals and Insects, like birds and wasps, also prey on Japanese beetles, which helps keep their numbers in check.

how to prevent Japanese beetles Chemically

When it comes to chemical approaches, you can use insecticides to kill or repel Japanese beetles. But you must be careful as these chemicals are harmful to many helpful bugs like bees and butterflies.

If you are taking any chemical approaches for Japanese beetles, it is necessary that you read the label for instructions and follow them thoroughly.

Most of the time, people use Carbaryl (Sevin) to get rid of Japanese beetles. This chemical can kill Japanese beetles within just a few hours.

Imidacloprid (Merit) is another viable choice that prevents the beetle from eating your plant. You can try chemical techniques but make sure they are used with caution.

Integrated Pest Management for Japanese Beetles

Integrated pest management is another approach to Japanese beetle control that works to lessen the effects of pests on the plant and its surrounding.

Monitoring the Japanese beetle population is an important part of integrated pest management which allows you to assess how your efforts to reduce the pest infestations have worked out.

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You can even use row coverings and nets to keep Japanese beetles away from your plants.

Preventing Future Japanese Beetle Infestations

Getting the Japanese beetle infestation in check can be stressful, which only makes you more vigilant for the next time it might happen.

You can take preventative measures to protect your home garden and houseplants from Japanese beetles. Here are a few measures you can take:

  • Remove any ripe fruit or vegetable as soon as possible from the plant since Japanese beetles are attracted to ripe or damaged fruit.
  • Remove dead leaves and any other item that might provide a home for pests from around your plants on a regular basis.
  • You can give row coverings and netting a try to protect plants from Japanese beetles.
  • If you are caring for your plants regularly by watering, fertilizing, and trimming them, all factors that contribute to plant health, your plant will be able to withstand attacks from insects.
  • You can also try growing types of plants that Japanese beetles don’t often infest or find appealing, including herbs like sage, thyme, and parsley, flowers like marigolds, and vegetables like onions and garlic!

Ideally, if you start incorporating these approaches a little early, you can reduce the chances of Japanese beetles attacking your home garden.

Japanese Beetle Control in Ornamental Gardens and Landscapes

People who love gardening take real pride in the work they have done with their ornamental gardens and landscapes for resting and entertaining.  

Unfortunately, Japanese beetles’ insatiable eating habits may rapidly convert this paradise into a nightmare.

  • The first thing you can do is find out which one of your plants is attracting Japanese beetles. Once you have found the plant, you must check it for the symptoms of Japanese beetle infestation.
  • These signs include skeletonizing, flowers nibbled on, or missing petals. Ideally, you can handpick the Japanese beetles off the affected plant.
  • Or you can apply insecticidal soap or neem oil directly on the plant that is infested with Japanese beetles.
  • You can also give the chemical control approaches a shot. You can use methods like pyrethroid-based pesticides as a last option since they are harmful to other helpful insects, too, such as bees and butterflies.

Lastly, you might want to stick to some plants that do not attract Japanese Beetles to avoid future infestations.

You can either choose to take extreme measures to keep your garden safe from Japanese beetles or start planting vegetables, herbs, and flowers that Japanese beetles don’t devour!

Japanese Beetle Control in Vegetable Gardens

If you are growing your own fruits and vegetables at home, you know that the Japanese beetles will try to attack your plants’ leaves and flowers.

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Taking precautions is important to keep Japanese beetles from taking over your veggie garden. One of the best ways is, of course, picking these insects by hand!

  • It is best if you try to handpick Japanese beetles off your plant early in the morning since they are much slower. Handpicking is time-consuming, but it is also extremely effective.
  • You can also try row covers and nets on your vegetables since they keep adult Japanese beetles away from the plants.
  • Another way is you could just put insecticidal soap or neem oil on the plants that have been damaged.
  • You can also take the chemical approach, but before using any harsh chemicals, it’s important to read the directions carefully and make sure they are safe for foods that will be eaten.
  • By growing partner flowers near your veggies, you may also reduce the number of Japanese beetles by attracting natural enemies like birds and helpful insects like ladybugs and lacewings.
  • Keeping your dirt healthy with good watering and fertilizing will make your plants more resistant to pests in general.

By taking these steps, you can keep Japanese beetles away from your veggie garden and keep it growing well!


Q: Are Chemical Pesticides Effective In Controlling Japanese Beetles?

Yes, chemical pesticides are effective in controlling Japanese beetles.

However, they should be used with caution and according to label instructions to minimize risks to humans, pets, and the environment.

Q: How Can I Prevent Japanese Beetles From Infesting My Plants In The First Place?

To prevent Japanese beetles from infesting your plants, you can try planting resistant varieties of plants and taking good care of your plants by removing dead and diseased plant material.


Although Japanese beetles can be difficult to remove, following the right information and techniques, you can reduce their effects on the plants and even prevent them.

Some ways to get rid of Japanese beetles, such as handpicking and bringing in their natural enemies, can be successful.

Even though chemical control methods work, they should be used carefully and in conjunction with other methods.

Integrated pest management is a complete way to get rid of Japanese beetles by using more than one method.