Dorothy is a master gardener, former newspaper reporter, and the author of several books. Michael is a landscape and nature photographer.
Are Ladybugs Ever Harmful?
All ladybugs have gluttonous, insatiable appetites for aphids and other insects, and that's a good thing. Some of them, however, can be more of a nuisance than a benefit.
Types of Ladybugs: the Good, the Bad, and the Bright
- The "good" ladybugs are the ones that stay in your garden devouring all the insects that invade your plants, seeking shelter outdoors when the weather is cold.
- The "bad" ladybugs have the same voracious appetite for aphids and other destructive bugs, but, unfortunately, they like to come indoors when it gets cold. When they do come inside, they emit a terrible odor and leave large yellow stains around your house before they die.
- The really "bright" ladybugs are the ones that are the most toxic to some animals. Fortunately (especially for your beloved pets), their bright color and the fact that they emit an extremely foul odor keep most predators away.
Ladybugs Are Seen as Good Luck
Superstitions surround just about everything on the planet, and the ladybug is no exception. Where and how a superstition begins is always open for a debate, but in the case of the ladybug, more than likely the thought that "If you harm a ladybug, you will have bad luck" was introduced by either a full-time farmer or a flower gardener. Both of these professionals would have good reason to keep young boys from killing the one thing that allowed them to have a successful crop.
That superstition, however, was developed in other directions (but always pointed at good fortune), and women in the Victorian era actually believed they would receive something new if a ladybug were to land on their bodies:
- If a ladybug landed on their hand, they thought they might receive a new pair of gloves.
- If it landed on their head, a new hat might be in the near future.
In more modern times, superstitious people believe their wishes will come true should a ladybug decide to land on them anywhere.
They Bring Luck by Eating Aphids and Other Garden Pests
So, even though the common ladybug is native to America, there are people around the world who believe that it is a symbol of good luck. And, if you are a farmer with hundreds of acres of crop or simply someone who loves to raise a beautiful flower garden, it truly could be, because the ladybug lives to devour aphids, whiteflies and other bugs that wreak havoc on your plants.
Photo Guide: The Four Stages of the Ladybug's Life Cycle
The "Bad" Ladybug
The Asian Lady Beetle
The Asian Lady Beetle is an exception to some of the things you've read so far about the benefits of having ladybugs in your garden. This cute little creature can be very aggressive and may even bite if they make contact with your skin, so they probably won't be your ladybug of choice for protecting your plants.
The first Asian Lady Beetles were found in the United States in about 1988, so they are relatively new to America. They are, however, native to Asia and hang out in trees and fields feeding on aphids and scale insects. In Japan, they are often found in soybean fields, but in the United States, they inhabit crops like roses, soybeans, alfalfa, tobacco and corn crops.
Leave Them Alone and Let Them Work
The Asian Lady Beetle, like other ladybugs, can devour hundreds of aphids a day (and thousands in its lifetime) so, while they can be beneficial to your plants, you still have to remember that they might bite, so you need to simply leave them alone outside and let them do their work. Let's discuss how to identify them, because Asian Lady Beetles like to come indoors and you won't want them there.
How to Recognize an Asian Lady Beetle
There are some ways to distinguish the "bad" from the "good" ladybugs.
- "M" or "W" Design: The Asian Lady Beetle looks a lot like the good ladybug, but the main difference is that they have an "M" or "W" design right behind their head in an area that is a whitish color.
- Color and Spots: They can come in a variety of colors, as you can see from the photographs in this article. Most of the spots on the Asian Lady Beetle are dark and black, whereas others have lighter spots, with some having no spots at all.
- Intolerance for Cold Weather: Asian Lady Beetles don't like cold weather and have been known to crawl into any cracks of a home they can find, eventually making their way inside looking for warmth.
In the life cycle of a ladybug, all of the stages are the same for the Asian Lady Beetle as for the common ladybug, so the only way you would probably be able to distinguish one from the other is in the adult stage when the marking becomes visible behind the head.
Problems With Asian Lady Beetles Inside the House
Once they get inside your house, they will fly around and leave disgusting, smelly yellow fluid that will stain your furniture, walls, ceilings, and any other surfaces on which they might land.
If you have several Asian Lady Beetles that have made their way into your home, you might even suffer an allergic reaction to them. Problems such as hay fever, hives, asthma, coughing or even pink eye have been known to occur, not only from touching the beetles but by simply being around a large infestation of them.
How to Prevent and Deal With Infestations
Pest-proof your home by sealing any and all cracks through which they might enter. If, despite your best efforts to keep them out, they still are in your home, simply vacuum them up or use a sticky tape to get rid of them. Squashing them will only cause more stains and more odor.
Ohio State University has a detailed website about the Asian Lady Beetles that will answer just about any questions you have about them. To access it, click here.
The Brighter the Ladybug, the More Toxic It Is
A study that was published in Scientific Reports journal suggests that the brighter a ladybug is, the more toxic it is to some animals. The same report also revealed that the more conspicuous the beetle is, the less likely it is to be attacked by predators. Their bright colors apparently serve as a type of warning to potential predators that the beetles are not afraid to use their extremely foul-smelling, poisonous chemicals for self defense purposes. Apparently, the brighter the ladybug, the more disgusting it tastes.
The study was the first to show how the color and/or conspicuousness of the ladybug reveals their level of toxicity, and determines whether or not they are likely to be attacked by predators.
They might as well be wearing a sign that says: "Eat me and I'll make you vomit!"
But Ladybugs Are Never, Ever Ugly!
Although ladybugs in the pupa stage have a bit of an "alien" look to them, try to remember that eventually they are going to turn into a gorgeous, aphid-munching machine. That's when they will become truly appreciated as natural (and really cute) pest control solutions.
So, they are never, ever ugly!
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Questions & Answers
Question: When is the best time to release lady bugs to your garden if you buy them?
Answer: If you were referring to the time of day, they should be released in the early evening hours. If you release them when the sun is out they will fly away immediately.
© 2017 Mike and Dorothy McKenney
Braylyn Campbell on June 25, 2020:
I love it
Mike and Dorothy McKenney (author) from United States on May 27, 2020:
I am so happy you found the information useful. Keep reading!
Mike and Dorothy McKenney (author) from United States on April 30, 2020:
There are many that fit that description so I would Google "black caterpillar with orange spots" and look at the images to see which one you have. Some are bad and some are good so I agree with you that you need to know what it is before you unleash it on your plants. Thanks so much for reading.
Catherinesmith34@tiscali.co.uk on April 30, 2020:
I have just found a tiny bug looks like catapillar but is mainly black with orange spots, dont want to release till i know it wont spoil my plants
Mike and Dorothy McKenney (author) from United States on April 13, 2020:
Thank you; sorry to hear about the destruction of your plants!
Harry Chiangrai Thailand on April 12, 2020:
There are many groups taken the place on my longbean plants and distroying all the fruits and trees. They are very small size and not like beautiful ladybugs.
Any how wish you happy easter 2020.
Mike and Dorothy McKenney (author) from United States on September 17, 2019:
Thanks for reading!
Xyz on September 15, 2019:
Mike and Dorothy McKenney (author) from United States on June 09, 2019:
And YOU are nice to read my article! Thanks!
Caela on June 08, 2019:
You are nice
Mike and Dorothy McKenney (author) from United States on August 04, 2018:
Yes, of course. Send it to email@example.com
Becca on August 03, 2018:
I have a video of a bug that I think is an Asian ladybug beetle giving itself a bath? I wondered if I could email it to you??
Mike and Dorothy McKenney (author) from United States on May 30, 2018:
I have done some preliminary research and I think you may be looking at Cowpea Curculio beetles. Check out the information on the internet about these and let me know if you think they are the problem. Thanks so much for reading my stuff and I hope I am able to be of assistance to you.
Mike and Dorothy McKenney (author) from United States on May 30, 2018:
Would it be possible for you to send me a picture to my e-mail address? Without seeing the bugs to know exactly what they are, I would be afraid to give you bad information. If you can, send me a photo to firstname.lastname@example.org - Thanks!
Monthailand on May 30, 2018:
Hi I'm a new gardener living in Thailand. I've found bugs that I've never seen before. From my searching they look like steel blue ladybird but I'm not sure what they are. I'm trying to search on Thai website but nothing pop up about that bugs. The bugs are all over my bean plants and starting to go on my green long egg plants. What should I do?
Mike and Dorothy McKenney (author) from United States on November 06, 2017:
Thank you so much!!
And Drewson from United States on November 06, 2017:
Very nice article.