Japanese Beetle vs. Asian Lady Beetle vs. Ladybug: 4 Key Differences

Three insects with similar sounding names: but which one is which? Let us explore the major differences between Japanese Beetle Vs Asian Lady Beetle Vs Ladybug.

Given the amazing diversity of the insect world, distinguishing one species from another may sometimes feel challenging. 

If you’re a nature-lover and enjoy learning about every new bug that makes your garden its home, you have ended up on the right page. 

We have explored the differences between Japanese beetles, Asian lady beetles, and ladybugs and put down our findings in the article below.

What Are Ladybugs?

Most of us are familiar with these beautiful insects. Known for their distinct black-spotted red bodies, these bugs are common in gardens and are a species native to North America. 

They belong to the Coccinellidae family and have earned a great reputation as a natural predator of various common garden pests. 

Ladybugs have dome-shaped bodies with a round or elliptical structure, and their black heads have a couple of white markings on the sides.

What are Asian lady beetles?

The Asian lady beetle, or Harmonia axyridis, is also a member of the Coccinellidae family. You might easily mistake them for ladybugs or vice versa, thanks to the similarities in their appearance. 

Like ladybugs, Asian beetles have dome-shaped bodies with black spots. However, the primary color may vary from red to orange.

The head of an Asian lady beetle is white, with a black M-shaped marking. 

Another way to identify lady beetles is reflex bleeding – a behavior triggered when they feel threatened. 

It involves releasing a toxic yellow liquid with an unpleasant odor from their leg joints. Indoors, they often cause a nuisance by staining curtains and other surfaces with this liquid.

What are Japanese Beetles?

Unlike the other two beetles described above, the Japanese beetle belongs to the Scarabaeidae family. This invasive species is a notorious pest, infamous for the heavy damage it causes to plants. 

Although they look nothing like Asian lady beetles, the name might make one think they’re at least related to each other. 

Their copper-brown wing covers and metallic green thorax and head make them quite easy to identify.  

Ladybug vs. Asian Lady Beetle vs. Japanese Beetle – Key Differences

In case you’re having a hard time differentiating between these three bugs, the following information should help you out. Here are the key differences between ladybugs, Asian lady beetles, and Japanese beetles:

1.    Appearance

Let’s begin with how you can visually distinguish these bugs from one another.

While the Japanese beetle looks completely different, ladybugs and Asian lady beetles are easy to confuse for each other unless you know the differences.

Size: The size of a ladybug can vary greatly, ranging from 0.03 inches to 0.71 inches.

The Japanese beetle is somewhat close in size and grows up to 0.6 inches.

However, Asian lady beetles are far smaller, growing to a length between 0.2 inches and 0.33 inches.

Body shape: Both Asian lady beetles and ladybugs have dome-shaped bodies, which is one of the reasons why they’re often mistaken for each other.

However, while a ladybug’s body is closer to a perfect circle, an Asian lady beetle has an oval body.

The Japanese beetle lacks a dome-like structure, and its body shape is more like a particularly long egg.

Color: This is another aspect where ladybugs and Asian lady beetles are somewhat similar.

Both have bright bodies with round black spots. However, a ladybug is red, whereas the color of an Asian lady beetle ranges from red to orange, and they have black and white heads, respectively.

Japanese beetles look completely different, with metallic green heads and thoraxes and copper brown wing covers.

Other visual differences: While all three of these bugs have a pair of antennae each, those belonging to the Japanese beetle are somewhat club-shaped. Besides, it also has six small tufts of hair along the sides.

As you can see, there’s no way one can confuse a Japanese beetle for a ladybug or an Asian lady beetle due to its appearance. 

Although the other two look similar to each other, a close look will still help you distinguish them.

2.    Habitat and distribution

As mentioned earlier, not all three of these bugs are native to North America. Let’s have a look at the habitats where you’re likely to find them.

Origin: The Asian lady beetle, as the name suggests, originated in the Asian countries of China, Korea, and Japan.

They were deliberately brought to the US in a regulated manner to control agricultural pests.

They grew in numbers and became a common bug throughout the United States in the 1990s.

As the name suggests, Japanese beetles are native to Japan. In the US, they were first seen in New Jersey in 1916.

It took them some time to grow in numbers, but by 2001 there were plenty of these beetles in the US. 

Current geographic distribution: Ladybugs are the most widespread among the three – you can find them almost all over the world except the polar regions.

The Asian lady beetle has spread around the world as well, including Europe and the Americas.

Japanese beetles are relatively less common, found mostly in Eastern Asia, North America, and Europe.

Preferred habitats: Japanese beetles, Asian lady beetles, and ladybugs are all found in grasslands, forests, farms, and cities.

Additionally, ladybugs are also quite common in suburbs and along rivers.

You should note that while ladybugs and Japanese beetles rarely get indoors except by accident, the same can’t be said about Asian lady beetles.

They often make their way in through cracks around windows and other access points, especially to overwinter.

Hence, although these bugs have different origins, there’s a good chance that you might them. Their feeding habits draw them to areas with vegetation, which means your property is more likely to attract them if it has a garden.

3.    Risk to humans

When you come across a new bug, one of the first things that might come to your mind is whether they pose a threat. Let’s find out if any of these three bugs are a risk to humans.

Bites: Both ladybugs and Asian lady beetles are capable of biting and pinching. Their bites or pinches can leave behind marks on the skin.

While Japanese beetles might try to do the same, their mandibles aren’t strong enough to hurt humans. They cannot even damage the skin in any way.

Toxicity: When threatened, Asian lady beetles release a liquid known as hemolymph in self-defense.

This smelly liquid is potentially toxic and may trigger allergic reactions in humans, but the toxicity level is rather low.

Ladybugs carry mild toxins, too but aren’t poisonous to humans. Japanese beetles do not secrete any poisonous substances and are harmless to humans.

In this regard, you might want to remember that while Japanese beetles don’t pose a risk to humans, they cause the most devastating damage to gardens and crops.

4.    Feeding habits

Moving on, let’s explore the feeding habits and preferred diets of the bugs in question. This is also the aspect that makes ladybugs and Asian ladybeetles beneficial insects.

Ladybugs: Ladybugs are insectivores that feed on various small and soft-bodied insects.

These beautiful beetles are one of the most beneficial insects out there, preying on aphids, fruit flies, and other common plant pests.

Even a single adult aphid can devour as many as 75 aphids in a single day.

Asian lady beetles: Like ladybugs, the diet of an Asian lady beetle primarily consists of small insects too.

However, it has a much wider range of prey compared to lady bugs and can eat hard-bodied insects.

In addition to pests like thrips, aphids, and mites, this species of lady beetle also preys on other beneficial insects, including native ladybugs.

Japanese beetles: Now, this is where Japanese beetles are the complete opposite of ladybugs and Asian lady beetles.

Rather than being natural predators that help in pest control, Japanese beetles themselves are major pests.

These beetles feed on more than 300 different species of plants, fruits, flowers, and leaves, causing heavy damage.

Hence, while it’s perfectly fine to let ladybugs and Asian ladybeetles stay in your garden, you’d want to get rid of Japanese beetles as soon as possible.

The extent of damage they cause has even earned them the reputation as the worst landscape pest in America.  

How Do You Know if Japanese Beetles Have Damaged Your Plants?

Until you specifically see the pests, it might be a little hard to figure out what’s damaging your plants.

Well, inspecting the damage closely might help you find out if it was Japanese beetles. Check for the following signs:

These beetles have a distinct eating pattern – they leave the leaves looking lacy. This is because Japanese beetles dislike the veins in the leaves and, therefore, just eat around them. 

Japanese beetles start from the top of a plant and work their way to the bottom. The location of the damaged leaves can therefore act as an indicator too.

As Japanese beetles infest in large numbers and eat together, you’ll notice the damage spreading rapidly.

These bugs are more active during the day and love sunny weather. Hence, there’s a good chance that you’ll get to see them in action anyway.

How To Get Rid of Japanese Beetles?

As mentioned earlier, Japanese beetles can be a huge menace in your garden. In the unfortunate event of finding them feeding on your plants, here’s what you can do to get rid of these pests:

1. Pick them off by hand

Picking off Japanese beetles by hand is the simplest way to deal with them. Their size makes them easy to grab and hold, unlike many smaller pests. 

To kill them, just throw them in water with a few drops of detergent mixed in it. If you aren’t comfortable with touching bugs, wearing nitrile gloves should help.

2. Natural insecticides

Natural insecticides like neem oil are very effective against Japanese beetles. Neem oil, in particular, contains a substance named potassium bicarbonate that’s fatal to the grubs. 

Adult beetles feeding on plants sprayed with neem oil pass it on to the grubs, thereby causing them to die. 

You may also make use of germaniums – they contain a substance that paralyzes adult Japanese beetles.

3. Use trap plants

This is a smart technique that works well against a variety of pests. Get yourself a plant that Japanese beetles are particularly fond of, such as primrose, African marigold, borage, knotweed, etc. 

Use it as bait to lure all the beetles to one place, from where you can easily handpick or vacuum them up. 

Using trap plants is a particularly good idea when you are dealing with a large beetle infestation spread across your garden.

4. Bring in the natural predators

Biological control of garden and agricultural pests through the use of natural predators is highly encouraged as a long-term pest control strategy. 

Birds are the biggest predators of Japanese beetles, and they eat them in large numbers. Simply setting up a bird bath and a bird feeder will help you attract more birds. 

Certain birds, like crows and starlings, also prefer to feed on the larvae of these beetles, known as grubs.

5. Spray nematodes

Although nematodes also count under natural predators, they deserve a special mention here. These microscopic soil-dwelling worms voraciously prey on grubs. 

You can find nematodes at a store that sells beneficial insects for gardening and agricultural purposes. 

Due to their size, you need to apply them by spraying. It’s best to apply nematodes in spring or fall, and you need to reapply them every year.

6. Use dead Japanese beetles

We know this might sound like a weird and potentially gross method, but you can use dead Japanese beetles to repel the living ones. 

Simply putting containers of dead Japanese beetles near your plants should be enough, as long as their smell can escape the container. 

It’s the smell that acts as the repellant. 

Besides this, it’s also possible to make a repellant spray from dead Japanese beetles by putting them in an old blender with some water and liquifying them. 

You can then strain out the solid body parts and use the liquid to spray your plants.

7.  Bacillus Thuringiensis (BT)

Bacillus thuringiensis is a pathogen that is derived from bacteria residing in the soil. It is parasitic to most pests, including the Japanese Beetle. 

You need to give it two to three weeks time to take effect, and the best way to spread is through spraying.

Most importantly, BT is not toxic to other beneficial insects, which makes it a perfect insecticide.

Wrap Up

If you previously had trouble distinguishing these three bugs, I hope this article has helped clear up your confusion. 

Besides, you now also know which ones are good for your garden and which ones aren’t. If you spot any Japanese beetles in your garden, take the necessary steps to eliminate them immediately. 

The presence of Japanese beetles draws more of them to your garden, which means the quicker you kill them, the better. 

Thank you, and we hope the long read has been worth it.