Are Asian Lady Beetles Harmful?

Asian Lady Beetles look almost the same as native ones, but these bugs can be a pest. In this article, we look at what harms they cause and how to deal with them.

Have you ever come across yellow stains on your curtains or table that have a foul acidic odor? Well, these stains might be the work of the Asian Lady beetles.

These small colorful insects were originally found in countries like China and Japan but have traveled to different parts of North America as well.

While they are beneficial for farmers and gardeners, these insects can be harmful if you don’t know how to control their population.

This article will discuss all the details about Asian Lady beetles and how to control them.

What Are Asian Lady Beetles?

The Asian beetles are native to the Asian countries Russia, Korea, Japan, and China. However, they are an invasive species here and were first reported in the US in Louisiana in 1988.

The adult lady beetles are about 0.25 inches in length and oval in shape. They have red or orange-colored bodies with black spots on the wing covers.

They lay eggs that are yellow, which produce orange and black colored larvae. The adult beetle and the larva consumes aphids and other soft-bodied insects.

Are They Harmful?

These insects do not infest wood, fabrics, or food. Also, they do not carry any diseases. In fact, they even help control the population of dangerous pests like aphids.

Despite these qualities, the Asian lady beetle population can be a problem to deal with. Let us find out why.

Do They Bite or Sting?

Yes, these beetles can bite when they feel threatened. An Asian lady beetle’s bite is strong enough to tear the human skin and cause great pain and discomfort to the victim.

Therefore it is important to be careful around these insects.

One more important thing to note is that continuous exposure to these ladybugs can trigger allergic reactions in the human body.

If you are allergic to them and are exposed, use ibuprofen to help reduce the pain. Also, rush to the nearest hospital to get a shot in case you see a severe reaction.

Can They Enter Homes?

Yes, these ladybugs can easily enter homes using the tiny openings and cracks in the doors, windows, vents, and more.

If you have gaps around your windows or walls, these insects will definitely use them as entry points.

Although they do not cause any harm to the interiors of your house, these insects secrete a foul-smelling yellow liquid when they are disturbed. This liquid can leave a big stain mark on your clothes.

Are They Poisonous/Venomous?

As mentioned above, these bugs can inflict a good amount of pain through their bites, but you will be relieved to know that the Asian lady beetles are not venomous.

However, it is always wise to approach them carefully if you don’t want to be bitten or stained.

Are They Pests?

You can usually find these lady beetles in agriculture fields, home gardens, and woods.

They primarily depend on aphids to fulfill their diets, but when they run out of aphids to prey on, they shift their focus to consuming fruits like apples, grapes, and more.

These beetles will eat apples that are already attacked by birds or other pests. They usually prefer eating ripe apples.

If you find apples with large cavities or a foul taste or odor in your garden, it is probably these beetles feeding on them. Hence if you have apple trees in your yard, you might not want the ladybugs around.

Other Problems They Can Cause?

Although these insects are great for pest control, they are not welcome inside homes due to the fact that they can bite and leave smelly yellow stains throughout the house.

More importantly, it is almost impossible to stand the presence of these small insects roaming inside your house.

Therefore in the next section, we will discuss a few ways to get rid of them from your house.

How To Control Asian Lady Beetles?

To prevent these beetles from entering your house, make sure that you thoroughly check the house for cracks that can be entry points.

If you find such spots, seal them immediately. Do not ignore even tiny gaps around windows; these beetles can enter through a crevice as small as 1/8-inch in size.

You can seal these cracks with silicone and acrylic materials. Replace damaged door and window frames as well.

You can also use insecticides to limit the entry of these beetles.

Spray insecticides like cypermethrin, permethrin, bifenthrin, and more during the months of September and early October in your garden to get rid of them.

Frequently Asked Questions

Wrap Up

The Asian lady beetles are a highly beneficial insect due to their active pest-controlling ability, and gardener prefer having them around.

However, they are also capable of causing allergic reactions in humans and leaving behind nasty bites.

Moreover, the Asian lady beetle can also become a pest for apple plantations themselves. Therefore, it is important to learn about these insects to be able to handle them better.

We hope this article provides all the necessary tips and tricks that you need to handle these insects carefully.

Thank you for reading the article. 

Reader Emails

Asian lady beetles are an invasive species that can be quite a pest when they get inside your home. Read through some of the letters from our readers to understand just how bad they can get!

Letter 1 – Invasive Multicolored Asian Lady Beetle Larva eats Native Lady Beetle Larva

 

Subject: Another reason to hate Asian Lady Beetles Location: Central MN August 14, 2012 8:21 am Hello bug nuts! I found this (presumed) native lady beetle larva in our garden last night, and then another on a different milkweed. But the second was being consumed by a much larger lady beetle larva, (presumably) of the Asian Lady Beetle variety. Our milkweeds are being bombarded by another exotic species, the Oleander Aphid, so this ladybug on ladybug violence just seems unnecessary. Thanks again for your exceptional site! I visit it everyday. Signature: Don J. Dinndorf

Hi Don, Thank you for submitting this heartbreaking documentation.  We doubt there is little that can be done regarding the invasion of the exotic Asian Multicolored Lady Beetles as they have already become established coast to coast in North America.  It has long been known that native Lady Beetles are becoming scarcer, but the reasons are not fully understood.  The Agricultural Landscape Ecology Lab at Ohio State University is conducting a study.  We don’t know if this cannibalism is documented elsewhere, but we will try to find out additional information.  We did locate this article entitled Predation and cannibalism of lady beetle eggs by adult lady beetles by Ted E. Cottrell.  We have long thought that the Oleander Aphids are seriously compromising our native Indian Milkweed here in Mount Washington, Los Angeles, CA.  When the Oleander Aphids are plentiful, the milkweed gets a type of mildew.  The problem is further exacerbated because the Argentine Ants protect and disperse the Aphids because they want the honeydew.  Plants with dense Aphid populations are not producing seeds.  We will try to figure out what species your native Lady Beetle Larva belongs to.  Here is information from the USDA fact sheet on the Multicolored Asian Lady Beetle:  “Multicolored Asian lady beetles have become a problem in some regions of the United States. It is probable that their introduction into new habitats in the United States freed these lady beetles from some natural population checks and balances that occur within their native Asian range. It is likely that these natural controls will catch up to the lady beetles in time and curtail their booming population. Additionally, a period of time may be required for checks and balances of our native lady beetles to adapt to this newcomer.”  The Multicolored Asian Lady Beetle is still considered to be a beneficial insect and it is expected that its population will eventually stabilize and it is unknown if its presence is responsible for the decline of native species.

 

Letter 2 – What Parasitized the Multicolored Asian Lady Beetle?

 

Subject: Some sort of parasite? Location: Lafayette, NJ July 12, 2016 12:53 pm I found a most curious thing today while out hiking – an asian multicolored lady beetle with it’s shell open, wings extended, and what appears to be some sort of growth or parasite on its back. I’ve never seen anything like this before and can’t come up with any explanation. So, hoping you can have a look at these photos and perhaps solve the mystery? Signature: Deborah Bifulco

Hi Deborah, Though we cannot at this time provide you with a conclusive identification of what parasitized this Multicolored Asian Lady Beetle, Harmonia axyridis, we hope that whatever it is will help reduce the populations of this invasive Lady Beetle that is displacing many native species.  Our best guess is that it is the pupa of a Tachinid Fly or some parasitic Hymenopteran.  According to Featured Creatures:  “All insects have predators, parasites/parasitoids, and/or pathogens. Ladybirds are not exempt. Larvae of Epilachna borealis and E. varivestis are attacked by a native tachinid fly (Aplomyiopsis epilachnae (Aldrich)) which specializes in the genus Epilachna. Larvae of E. varivestis also are attacked by a eulophid wasp (Pediobius foveolatus, see above). This wasp is a parasitoid of other epilachnine ladybirds in India, and was introduced into the USA specifically to control Epilachna varivestis. Another native tachinid fly, Hyalmyodes triangulifer (Loew), is less specialized, attacking larvae not only of Epilachna varivestis, but also of Coleomegilla maculata, several weevils, and a pterophorid moth. Perhaps the best known of the parasitoids of ladybirds is the braconid wasp Perilitus coccinellae (Schrank). It attacks adult ladybirds and to a lesser extent larvae and pupae (Obrycki et al. 1985). It attacks Coccinella septempunctata, Coleomegilla maculata, and several other species. Many other parasitoids and pathogens of ladybirds are not mentioned here for lack of space.” Thanks, Daniel – I just wasn’t quite sure what I was seeing, although some sort of parasite makes the most sense. Interestingly, I have been seeing more native lady beetle species this summer in our area – many more than in past summers.  I am very encouraged by this as I know the asian has really hurt our native species. Debbi