How To Get Rid of Japanese Beetles Naturally: Japanese Beetle Treatment

The Japanese beetle is a significant pest in gardens and outdoor green spaces, and given its invasive classification in the U.S., it is critical that gardeners and homeowners know how to get rid of Japanese beetles.

Without natural predators, these beetles can wreak havoc on your gardens and vegetable plants, which makes them frustrating to deal with.

This complete guide explains how to recognize and identify Japanese beetles at various life stages and explores the best natural controls for this troublesome pest, providing real answers for how to get rid of Japanese beetles.

Pest Control for Japanese Beetles in the U.S.

Since they were first introduced to the country more than 100 years ago, Japanese beetles have fanned out across the Eastern U.S., even into the Midwest and Central U.S. (see APHIS’ “Japanese Beetle Distribution in the U.S.”).¹⁶

Their success is due in large part to the lack of natural predators in this country, a non-native territory, and in part to their varied, ample diet.

This pest happily feeds on 300+ popular plants in U.S. gardens and farms, and it devastates plant life wherever it goes, even significantly impacting agricultural output.¹¹ As an invasive species, the Japanese beetle is federally regulated in the U.S., with quarantine on interstate movement to non-infested regions of the U.S., per Title 7 §301.48.¹⁷

With this in mind, it is more apparent than ever why pest control for Japanese beetles in the U.S. is so important!

 Japanese Beetle Control

Fortunately, there are several options for homeowners when it comes to Japanese beetle control. Not all of these options are equally effective, so it is crucial to be informed about the best methods for getting this invasive population under control.

The USDA/APHIS guide “Managing the Japanese Beetle: A Homeowner’s Handbook” is an excellent resource for individuals struggling with these troublesome pests.¹²

APHIS advises an integrated pest management (IPM) approach to combating Japanese beetles, as an established population can be very difficult to eradicate.¹²

An integrated approach may include observation and identification of beetles and their most populous areas, communication with neighbors and local resources (ex. the Local Cooperative Extension Office), and use of a wide range of control methods, including but not necessarily limited to:

• Chemical controls
• Physical controls
• Biological controls
• Ecological controls
• Mechanical controls

 How To Get Rid of Japanese Beetles With Japanese Beetle Spray (Japanese Beetle Killer)

Homeowners who are looking for the quickest option for how to get rid of Japanese beetles are more likely to be drawn to chemical controls such as Japanese beetle killer insecticides and Japanese beetle sprays.

The pesticides that are typically recommended for Japanese beetles are pyrethrin-based and neem oil-based.³

(Image: Jan Vasek²⁴)

While both of these pesticides have naturally derived components, neither is “organic,” and the potential for harm and contamination is still there, particularly with pyrethrin. Read the following fact sheets for more information on these chemical controls: Neem Oil Fact Sheet and Pyrethrin Fact Sheet.^18,19

When using these pesticides or insecticides, apply them when the first signs of plant damage become apparent. Spray directly on the affected plants. When the adult beetles feed on the treated plant, they will be killed.

 How To Kill Japanese Beetles Manually

There is some good news about adult Japanese beetles. They are slow-moving and easy to remove manually from plants.

The best method to kill Japanese beetles manually is to literally handpick them from plants and drop them into a bucket of soapy water, where they will drown.³ Although this method can be time-consuming, it is a highly effective strategy for dealing with Japanese beetles, particularly when used in conjunction with other pest control methods aimed at the larval stage of the life cycle.

Note that even when treating the larval stage of the Japanese beetle in the spring, it is still important to deal with any adult insects as they appear.

Eliminating adult beetles at first sighting can limit the number of times they are able to burrow underground and lay their eggs throughout the summer.

How To Get Rid of Japanese Beetles Naturally (Natural Japanese Beetle Treatment)

A century of dealing with these pesky insects has led to a better understanding of their life cycles, how they thrive and spread, and how they can be controlled. Methods for how to get rid of Japanese beetles, an outdoor pest, differ significantly from methods for how to get rid of Asian lady beetles and how to get rid of carpet beetles, predominantly indoor pests.

Amazingly, there are even several techniques for how to get rid of Japanese beetles naturally. These methods are going to fall into one of four categories: physical, mechanical, ecological, or biological controls.

 Physical Controls for Japanese Beetles

Physical controls for Japanese beetles, discussed briefly in the previous section, have to do with manually removing and killing the adult insect when found. Physical controls for the larval stage are not really practical, as they would require an individual to dig up large areas of their yard to remove the grubs.

Thus, physical control emphasizes the eradication of adult beetles on sight. It can also involve creating a physical barrier for plants, such as a drop cloth or netting.

These can serve a dual purpose of protecting plants and catching adult beetles, as the material can be scooped up in the early morning hours when beetles are most active and emptied into soapy water.²

 Mechanical Controls for Japanese Beetles

Mechanical controls have some overlap with physical controls and mainly involve the use of beetle traps. Japanese beetle traps can be purchased online and through local nurseries.

These traps are designed to lure and attract the pesky beetles before trapping them inside. Because they can attract insects from some distance, it is important not to put the traps too close to vulnerable or desirable plants.

A minimal distance of 25 to 30 feet from vegetation is advisable.^2,12 This is also an excellent method for observing Japanese beetle populations in the neighborhood.

 Ecological Controls for Japanese Beetles

Ecological control of pests is a rapidly evolving area in gardening and agriculture. It focuses on the prevention of pests through landscaping and gardening choices and designs.

Removing diseased plants and trees that naturally harbor pests is also a critical piece of the equation.

  Biological Controls for Japanese Beetles

Biological controls are debatably the most effective Japanese beetle treatment. Many biological controls are aimed at the more stationary larval stage of the life cycle, but some are specific to adult beetles.

Biological controls that target Japanese beetle grubs include:

• Nematodes: These parasitic roundworms (Steinernema glaseri, Heterorhabditis bacteriophora) can be applied to the affected soil in the spring.^20,21 The nematodes will seek out the grubs and inject the grubs with bacteria that devour the tissue of the grub.
• Bacteria: Certain strains of bacteria (Bacillus thuringiensis, Milky Spore Bacillus popillae) can be applied like insecticides to the soil in the lawn.^22,23 These bacteria effectively poison the grubs when ingested.

There are also parasites that can be employed against adult beetles, such as parasitic wasps and flies, but these can be difficult to source and obtain.¹²