Harlequin bugs are bright and colorful insects often found near crop plants. They are renowned pests of cruciferous vegetables, but are harlequin bugs harmful to humans? Can you pick them up by hand and throw them away like aphids? Let’s discover more.
Harlequin bugs (Murgantia histrionica) not only have a rather interesting name, but their appearance makes them unique too.
If you’ve spotted these bugs in your garden or suspect their presence, you might be wondering if it’s a cause for worry.
To answer your query quickly – yes, harlequin bugs are major pests and cause considerable damage to plants, especially vegetable crops.
Let’s not beat around the bush and find out more about these bugs, what kind of damage they cause, and how to get rid of them.
What Is A Harlequin Bug?
A common pest of cruciferous plants, harlequin bugs are native to North America.
Note that these bugs aren’t to be confused with the harlequin ladybird. Despite the similarity in their names, they are two entirely different species of beetles.
So, harlequin bugs aren’t a ladybug species at all – they’re a kind of stink bug notorious for destroying vegetable crops.
They are rather colorful, with varying patterns.
Some look a lot like orange-tinted ladybugs with black spots, while others might look like black ladybugs or brown ladybugs. The nymphs may have stripe patterns instead.
Do Harlequin Bugs Bite Or Sting?
Before trying to touch or grab any insect, it’s always a good idea to check if it can hurt you.
Harlequin bugs, for instance, possess piercing mandibles. These bugs are capable of both stinging and biting.
Thankfully, harlequin bugs usually aren’t aggressive and do not pose a serious threat to humans.
You should still exercise caution while handling them and avoid direct contact with the skin, as they can inflict localized pain.
Are Harlequin Bugs Poisonous Or Venomous?
Insects of bright color are usually poisonous, with the colors acting as a warning sign to deter predators.
Any toxic ladybug species, like larch ladybugs, would be a perfect example.
The harlequin bug, however, doesn’t have any poison. Instead, these bugs become extremely spicy due to the chemicals they consume from plants.
This keeps them safe from birds, as birds typically avoid spicy food.
Are Harlequin Beetles Beneficial?
Harlequin beetles are disastrous insect pests and can cause extensive damage to vegetable plants.
Piercing the plants in various places, they suck out the plant juices. The plants begin to wilt, turn brown, and eventually die.
So, Harlequin beetles aren’t exactly the kind of insect you’d consider beneficial.
They are more of a garden and agricultural pest.
However, they make it easier for gardeners to identify stressed plants, as those are the plants that usually get attacked by Harlequin bugs.
How Are Harlequin Bugs Harmful To Humans?
These pests are particularly known to attack cabbage, which has also earned them the name harlequin cabbage bug.
Other cruciferous plants like cauliflower, broccoli, kale, turnip, radish, etc., are at high risk around them too.
If the usual preferences are unavailable, harlequin bugs turn to other crops like tomato, okra, squash, corn, and beans.
These bugs cause a great deal of damage and can destroy entire crops if left unchecked.
They attack and feed on almost every part of a plant – the stems, leaves, fruits, and seeds alike.
You may think of the kind of damage to be similar to that caused by Asian ladybugs, except it’s more severe for harlequin bugs.
How To Get Rid Of Harlequin Bugs?
Moving on, let us check out how you can rid your garden of these annoying and destructive pests.
Depending on the stage of infestation and the relative effectiveness, you may try the following solutions.
Handpicking and vacuuming
If it’s just a small number of bugs, you can gently pick them off the plant by hand and throw them in a bucket of soapy water.
Using warm water for this solution will make it even more effective.
Be careful not to squish harlequin beetles as they’re a kind of stink bug and can emit pungent odor as a defense mechanism.
The other option is to take a vacuum cleaner and run it over the infested plants.
Parasitoid wasps
The use of natural predators is one of the best long-term pest-management techniques.
Non-stinging parasitoid wasps are good at destroying Harlequin bug populations.
One can either buy the wasps online or plant companion plants that attract such natural enemies.
You should note that the braconid wasps usually used in garden pest control don’t do much against these bugs.
Trap crops
Get a crop of cruciferous veggies early on before you grow the main batch of produce.
The early trap crop will draw away most of the harlequin bugs and keep your main crop safe.
You can dispose of the trap plant after harvesting the main crop.
Insecticidal soap
You can spray an insecticidal soap solution to effectively kill the bugs. The soap can penetrate their hard shells.
However, it works as a direct-contact insecticide – you need to spray the solution directly on the adult harlequin bugs, nymphs, and eggs.
Diatomaceous Earth
This reliable insecticidal agent works against a variety of pests, including Harlequin bugs.
You can sprinkle diatomaceous earth over the bugs as well as apply it over the crops.
It destroys the waxy coating on the bugs’ bodies and dehydrates them to death.
Bug Control Recommendation Tool
Should You Kill Them?
Unfortunately, you don’t have much of choice besides killing harlequin bugs that attack your plants.
Unless you take the necessary steps to get rid of these bugs, they can cause extensive damage to your vegetable crops, fruits, and ornamental plants.
Unlike the black and orange ladybugs that help gardeners by preying on harmful pests, the harlequin bug itself is a pest.
Frequently Asked Questions
What damage do harlequin bugs do?
Harlequin bugs are pests that cause serious damage to vegetable crops. They feed on various plants, including squash, cucumber, bean, and tomato plants.
The harlequin bugs suck sap from the leaves of the plants, causing yellowing and wilting of the foliage.
In some cases, the entire plant can be killed by this pest.
Are harlequin beetles beneficial?
Harlequin beetles are beneficial to their ecosystems because they feed on decaying wood, returning nutrients to the soil and encouraging new plant growth.
They are also necessary as part of a food web, as they provide food sources for other animals such as birds, frogs, and lizards.
Harlequin beetles also play an important role in controlling pest populations by preying on grubs and maggots.
Who eats harlequin bugs?
Harlequin beetles are a popular prey item for many different species of birds, reptiles, amphibians, and mammals.
They are also eaten by some ants, spiders, and even their own larvae.
The beetles provide a good source of nitrogen and other essential nutrients to these predators.
Additionally, Harlequin beetle cocoons are eaten by shrews, frogs, lizards, and other small predators looking for an easy meal.
How do you fight harlequin bugs?
To fight harlequin bugs, it is important to keep your garden clean of leaf litter and debris because this is where the harlequin bug lays its eggs.
If you find any in your garden, you should remove them by hand or use a powerful vacuum.
You can also try spot-treating the garden with an insecticide containing acetamiprid or neem oil-based products.
You can discourage insects from entering your garden by covering any bare soil with mulch or cotton balls soaked in water.
Another strategy is planting companion plants such as marigolds and carrots that are unappetizing to harlequin bugs.
Wrap Up
The harlequin bug isn’t uncommon in the United States, so it’s best to watch out for them and take the necessary pest control measures.
Avoid leaving plant debris in your garden, especially from cruciferous plants.
Thank you for reading, and I hope you can eliminate harlequin bugs in your garden before the infestation grows out of control.
13 Comments. Leave new
Hi
Does anyone know if a species of Harlequin beetles e.g. those in UK, carry mites?
Thanks, Andrew
Yes, some species of harlequin bugs can possibly carry mites so if you own them keep them in a cage!! ; )
Hi
Does anyone know if a species of Harlequin beetles e.g. those in UK, carry mites?
Thanks, Andrew
I am pretty sure this is actually the adult version of Spilostethus pandurus which is also seen in Cyprus but I have definitely seen a few in Portugal. I say this based on the brown wings that do not have a white ring, and the shoulders which have a continuous black marking all the way up to the head. The triangle at the top of the wings too is more narrow and sharper. Of course it would be better with the head in the photo but I believe it would only confirm it.
http://www.whatsthatbug.com/2014/04/25/firebug-nymph-cyprus/
Someday I’ll send in my pictures of Spilostethus pandurus as both adult and juvenile (don’t want to overwhelm you in the busy season — unless you signal otherwise as it is prime season for them now). They actually seem to have quite a lot of personality but tend to be lone bugs (perhaps because they can fly) rather than aggregate like the much smaller non-flying Fire bugs.
Oh, ha ha… perhaps you might consider putting in a section on Insect movies & docs. Seems there is one with a section on the perils of being a Japanese Red Bug Mama (Animal Planet & BBC), and one on the Japanese love affair with bugs just to get you started:
http://www.bbcamerica.com/earth-night/guide/life/insects/
http://www.post-gazette.com/ae/movie-reviews/2010/08/19/Beetle-Queen-documentary-explores-Japan-s-love-affair-with-insects/stories/201008190361
http://www.pbs.org/independentlens/beetle-queen-conquers-tokyo/
And of course there are also all the Bee movies such as Queen of the Sun. :^)
Hi Curious Girl,
We would love your images of Spilostethus pandurus and if you send them today or tomorrow, we may be able to post them prior to leaving town for a few weeks. Please use the scientific name as the subject line to catch our attention as our identification requests are increasing as you surmised.
I am pretty sure this is actually the adult version of Spilostethus pandurus which is also seen in Cyprus but I have definitely seen a few in Portugal. I say this based on the brown wings that do not have a white ring, and the shoulders which have a continuous black marking all the way up to the head. The triangle at the top of the wings too is more narrow and sharper. Of course it would be better with the head in the photo but I believe it would only confirm it.
http://www.whatsthatbug.com/2014/04/25/firebug-nymph-cyprus/
Someday I’ll send in my pictures of Spilostethus pandurus as both adult and juvenile (don’t want to overwhelm you in the busy season — unless you signal otherwise as it is prime season for them now). They actually seem to have quite a lot of personality but tend to be lone bugs (perhaps because they can fly) rather than aggregate like the much smaller non-flying Fire bugs.
Oh, ha ha… perhaps you might consider putting in a section on Insect movies & docs. Seems there is one with a section on the perils of being a Japanese Red Bug Mama (Animal Planet & BBC), and one on the Japanese love affair with bugs just to get you started:
http://www.bbcamerica.com/earth-night/guide/life/insects/
http://www.post-gazette.com/ae/movie-reviews/2010/08/19/Beetle-Queen-documentary-explores-Japan-s-love-affair-with-insects/stories/201008190361
http://www.pbs.org/independentlens/beetle-queen-conquers-tokyo/
And of course there are also all the Bee movies such as Queen of the Sun. :^)
I would like to know how Harlequin Bugs get about, do they fly? We have thousands here, we have to spray them or we would have NO fruit as where they suck goes bad and destroys the fruit, namely our nectarines & now they have migrated to the apples. So we are trying to work out a plan so thats why we want to know if they fly?
Winged adults are capable of flying.
I’ve searched everywhere for advice on eradication. Australian sites all recommend handpicking.
Handpicking is not an option however, (as anyone in an affected zone knows) This is because they breed rapidly in plague numbers and for every ten you pick, a thousand more hatch. Advising handpicking to control these bugs is like telling farmers to handpick in a locust plague.
US sites recommend chemical eradication however the products identified in the US are not available here.
Finally I strongly doubt these things are natives. I’ve never seen one on a native bush.
We had never seen them before moving to the Mornington Peninsula. They are a plague! Killing everything…. herbs, beans, peas, strawberries, all berries, nasturtiums, salvias, fennel, potato shoots & flowers, passionfruit… we even found them decimating corn tassles, then our corn wasn’t fertilised properly!
So far we have found only 3 ways to kill them.
Splat them. Fry them with a cooks torch.
Put boiling water into a bucket and shake them off the plants into the bucket.
Still millions around and we do these things morning and arvo.
They are shocking.
We even vac up leaves around the paving and yard. They even eat their dead!
Worst pest ever.
I’ve searched everywhere for advice on eradication. Australian sites all recommend handpicking.
Handpicking is not an option however, (as anyone in an affected zone knows) This is because they breed rapidly in plague numbers and for every ten you pick, a thousand more hatch. Advising handpicking to control these bugs is like telling farmers to handpick in a locust plague.
US sites recommend chemical eradication however the products identified in the US are not available here.
Finally I strongly doubt these things are natives. I’ve never seen one on a native bush.
We had never seen them before moving to the Mornington Peninsula. They are a plague! Killing everything…. herbs, beans, peas, strawberries, all berries, nasturtiums, salvias, fennel, potato shoots & flowers, passionfruit… we even found them decimating corn tassles, then our corn wasn’t fertilised properly!
So far we have found only 3 ways to kill them.
Splat them. Fry them with a cooks torch.
Put boiling water into a bucket and shake them off the plants into the bucket.
Still millions around and we do these things morning and arvo.
They are shocking.
We even vac up leaves around the paving and yard. They even eat their dead!
Worst pest ever.
put cheap dishwashing liquid into a spray bottle (double what you would use to do dishes) spray the bugs and it clogs up their gills and they die in a few seconds, I always have a couple of old spray bottles in the garden from spring at the ready