Looking for the best insecticides for Japanese beetles?
Perfect, you’re in the right place! In this guide you’ll learn:
- A little about Japanese Beetles and some of your options to combat them
- What are the top pesticides that exist to fight them quickly
- How to use pesticides to kill Japanese Beetles around your home and yard
And much more!
Ed has been working in the pest control industry for years helping 1,000's of homeowners navigate the world of insect and rodent management. He manages Pest Strategies now helping homeowners around the world!
Table Of Contents
6 Best Insecticide for Japanese Beetles
Are you short on time or just want a quick answer?
Check out our list below for a summary of our results. Keep on reading to learn more about insecticide for Japanese beetles.
What Are Insecticides For Japanese Beetles?
An insecticide for killing Japanese Beetles doesn’t refer only to the adult beetles. It must also be able to attack and kill the eggs and larvae that live underground for most of the year.
Surface sprays that only kill the adults can’t give you the control you need.
They are close to the surface during the late summer and early fall during warm weather. This is the time they are the easiest to kill.
The larvae move deeper underground during the winter, constantly growing and maturing. During the warmth of spring, they move toward the surface, but now they’re larger and more difficult to kill.
A true pesticide for eradicating Japanese Beetles must be able to attack them during all phases of their life cycle.
What Are The Different Types of Insecticides For Japanese Beetles?
There are two main types of insecticides for killing Japanese Beetles, curative and preventative. Let’s look at each one separately.
The traditional approach to the control of Japanese Beetles is to apply pesticides with a short-term residual impact after the eggs have been laid and before the grubs can cause visible damage to the turf and ornamentals in the yard.
The best time for curative treatments is early to mid-August. The grubs are still young, immature, and close to the surface where the pesticide can easily reach them.
This has become the more popular option because there is a larger window of time for application, usually from May to July. Another reason for the popularity of this method is the long residual impact of the insecticides used this way, up to a year in some cases.
These pesticides are applied before the eggs are laid. They kill the adults, the eggs, and the grubs that hatch from them.
How Do Insecticides For Japanese Beetles Work?
The active ingredient in each pesticide has a different mode of action. Some attack the central nervous system, others attack the respiratory system, and others focus on the muscles that control locomotion and circulation.
As long as they kill the beetles, it’s all good.
Are Insecticides For Japanese Beetles Dangerous To Pets or Children?
Yes and no. Children are often susceptible to chemicals and environmental effects that adults can safely ignore.
They have more skin surface relative to their body weight than adults, their liver and kidneys are immature, and they are closer to the ground.
Children also eat and breathe more in relation to their body weight than adults. Finally, infants crawl on the floor or ground then turn around and stick their hands (and anything they can grab) in their mouths.
All this makes them vulnerable to possible toxic effects.
Therefore, as a general rule of thumb, children should be kept out of areas treated with pesticides until they have completely dried. For some insecticides, that window might be longer and we’ll note it where appropriate.
Japanese Beetles can be tricky to start with because they start out as another problem. Most likely, if you see brown spots in your yard, that is the work of the Japanese Beetle larva, and treating those areas can get a head start on your problem.
Demand CS can also treat your plants directly if you are having issues with the beetle once it has transformed into its flying beetle phase of life.
Each bottle will make 10 to 20 gallons of product. This is great for your pocket as a little bit goes a long way, and the average homeowner will most likely use less than half a bottle a year.
It can be safely applied directly to the yard where the larva is growing in order to kill them directly or as a surface spray to kill the adults, making this one of the more versatile products for dealing with Japanese Beetles.
The Good And The Bad
- An entire bottle will last the average homeowner for more than a year
- This product kills Japanese beetles and their larva
- This product is safe to use on plants but should not be used on edibles
- Requires a sprayer to apply correctly
This pesticide was designed to kill pyrethroid-resistant bugs, although the second active ingredient, Metofluthrin, is a pyrethroid. The final active, Piperonyl Butoxide, is a synergist that makes the other two active more effective at killing bugs.
The combination creates a fast knockdown to kill adult Japanese Beetles. The residual impact begins working almost immediately as well. It is highly effective but each bottle only makes one gallon of finished product making it the most expensive one on our list.
It has a strong odor and the fumes have caused headaches in some people. Wearing a mask is strongly recommended. Pets and children should be kept out of the treated area for about 24 hours.
The Good And The Bad
- The active ingredients are Clothianidin, Metofluthrin, and Piperonyl Butoxide
- It kills pyrethroid-resistant bugs
- Quick knockdown
- Excellent residual impact
- Each bottle only makes one gallon of the finished product
- Strong odor can cause headaches
- Keep pets and children away for 24 hours
Organic 100% Neem Seed Oil
This product is OMRI (Organic Materials Review Institute) listed for organic farming. It is 100% cold-pressed Neem oil from Neem trees, the only ingredient in the bottle.
It can be used on fruits and vegetables right up to the day of harvest.
For soil drench treatments, mix one ounce of Neem oil with one gallon of water, so this 16-oz bottle will make 16 gallons of the finished product.
It’s very effective, especially against adult Japanese Beetles, but only for a few days. Then it has to be reapplied.
Because it is an oily extract, it may begin to solidify below 70ºF. If that happens, submerge the bottle in warm water for ten minutes then shake vigorously. For best results, mix it with warm water for making applications.
The Good And The Bad
- The active ingredient is Neem oil
- All-natural ingredients
- It is 100% non-toxic
- OMRI listed for organic farming
- Very effective against Japanese Beetles
- It has a very strong garlic odor
- It begins to solidify below 70ºF
- Only lasts for a few days
One application of these granules in the late spring or early summer will give you four months of control of Japanese Beetles in their white grub stage, killing them before they damage the turf in your yard. You’ll need a hand spreader to broadcast the granules.
One 28.7-pound bag of granules will treat 10,000 square feet. If you’re treating that much area, a push spreader may be worth the purchase price.
After spreading the granules, they need to be watered in so they’ll soak into the soil.
Keep pets and children out of the area until it has dried. If you’re not completely satisfied with the results, Scotts offers a money-back guarantee.
The Good And The Bad
- The active ingredient is Chlorantraniliprole
- One bag covers 10,000 square feet
- Last for four months
- Money-back guarantee
- Requires the separate purchase of spreader
- The granules need to be watered in after broadcasting them
- Keep pets and children away from the area until it is dry
If you are lucky enough to catch the signs that you are going to have a Japanese Beetle problem before the larva are able to leave their home in the ground, you can get ahead of the battle and possibly put an end to it before it ever becomes the headache that we all know it can become.
Japanese Beetles lay eggs in the ground that hatch and turn into a larva that then eats the grassroots around them and cause ugly brown spots to appear in an otherwise perfect lawn.
Merit Granules use Imidacloprid at .5% and come in a 30-pound bag. 1.4 pounds of these granules are capable of treating 1,000 square feet. For the average person, that means 3 to 6 pounds of this product will treat their yard every year and leave plenty left over for next year.
Granules work by using a spreader to evenly distribute them over an area, and then as it rains or gets wet by other means, the product is released and absorbed into the ground where it will kill lawn pests like the Japanese beetle.
Of course, you can sprinkle some directly onto a brown patch and call it a day, but to fully protect your yard, you will need some sort of granule or seed spreader to get a nice even coat to properly treat a larger area.
Where this product is less efficient than a liquid spray is that it doesn’t have any indoor applications. In addition to being outdoor only, and needing a spreader to use it effectively, it also isn’t usable near or on any kind of plant that is meant for food production purposes.
The Good And The Bad
- One bag will most likely last the average homeowner for more than a year
- It only takes 1.4 pounds to treat 1,000 square feet
- This product kills the Japanese Beetle Larva
- Outdoor use only
- Need a spreader to use it properly
Valent Safari SG Insecticide
This is a broad-spectrum insecticide that kills adult Japanese Beetles and their larvae as well as many other destructive pests.
One 12-oz bottle makes 50 gallons of the finished product. It is effective as a surface spray or as a drench treatment.
However, the active ingredient, Dinotefuranm, is highly water-soluble and mobile.
It also resists biodegradation, creating a strong potential for it to migrate into shallow water tables and cause contamination, especially where the soil is permeable.
Exercise caution when using this product as a drench treatment. If you’re not sure about the water table in your area, and can’t afford to pay for a professional survey, stick to using it as a surface spray to kill the adult Japanese Beetles.
The Good And The Bad
- The active ingredient is Dinotefuran
- One bottle makes 50 gallons of finished solution
- Broad-spectrum insecticide
- It has a strong potential for ground-water contamination