Discovering a hidden haven in the Latrobe Valley, Victoria, Australia

Harlequin bugs or Dindymus versicolour have been a spring and summer problem in my garden for a while now, but with good spring and summer rain this year they are doing a little too well. It seems they are playing havoc in a lot of local gardens right now as some of the most common searches that bring people to my blog involve variations on; dindymus, harlequin bug and ”Little red bug eating my plants”.

Adult Dindymus versicolour clustered on a rose leaf.

I’m also happy to say that I’ve learnt a think or two since I first naively posted about this little bug.

It wasn’t that long ago that I thought the Harlequin Bug was kind of attractive in its little soldier’s red coat and thought it was probably harmless.  After all, I could see that it was the caterpillars and the katydids that were doing the most obvious damage in the garden.To my own disgrace I later learnt that immediately obvious does not necessarily mean most significant. This is because Dindymus is a sneaky little sap sucker.

But I am surprised to find that there is still not a lot of information readily available about these bugs on the net, at least not in an easy to understand format in relation to gardening. Much of what I can find is either quite scientific or more people asking what they are and how to stop them eating their plants.

So, I thought I’d put together a collection of the bits and pieces that I have learnt. I am no scientist, so if anyone can see that what I’ve said is factually incorrect, please feel free to point it out! Additional references would be great too.

Identification

The Harlequin Bug I am referring to here is Dindymus versicolour and it is an Australian native. It is listed as a native pest species on the PaDIL biosecurity website found in NSW, Victoria, South Australia and Tasmania. Because the common name is the same, it has been mixed up with Murgantia histrionica from Mexico. Both are of the Hemiptera order. Dindymus versicolour is of the sub order heteropter, which is the ‘true bugs’. Some more information about this order of insects can be found here at the CSIRO website .

Mating pair and a young harlequin bug on a sunflower.

The photos give you an idea of their general appearance with black, red and orange/yellow making up their distinctive ‘harlequin’coat. Their undersides are a pretty green, sometimes with some yellow. However, there may be some colour variation.

The female is the larger of the species and they couple end to end while mating. Very young ones may just be red with a black spot and a little white around the margins. At a very cursory glance they can be mistaken for a ladybug.

Young harlequin bugs on a rose leaf.

Behaviour

For anyone looking at these little bugs in the garden and wondering if they are a potential problem or not the answer is a resounding ‘Yes!’

The Harlequin bug does not take great big obvious bites out of anything, it hides and sucks the life out tender stems (and fruit). Look for stem damage and wilting flower buds and fruit. In my garden I have observed them in greatest numbers on Callistemon, Australian native hibiscus, nasturtium, tomatoes, and hollyhocks. They have also been in numbers on sweetcorn, sunflowers, sage and roses.

visibly damaged tomato stems and one of many harlequin bugs from last summer.

These are one of the few bugs to actively hide from potential predators. If you watch them carefully you will notice that when they are not feeding they will stay in sheltered positions.  If they are caught out in the open they will dive behind leaves and stems as you approach. They don’t go far and sneak back out when you stop moving.

One or two bugs on their own won’t do much harm, but the sad reality is that this is often not a bug that comes in ones or twos. Not for long if you plant a tasty crop anyway. In numbers they can overwhelm tender plants, particularly nice juicy ones having a growth spurt.

Predators

I can’t find much information on the subject of predators. I haven’t observed anything eating these bugs and given the quantities they appear in, it seems natural predators don’t readily keep them in check. I think the question of predators is an interesting one. As they are a native species I would think something out there would have evolved to think they are tasty. Or have we wiped out their natural predators? This is a subject I’d like to learn more about!

Control

I avoid spraying with chemicals but these bugs have a tough protective coated shell which means that they can resist most sprays anyway.

The only sure-fire way I learnt to deal with them was thanks to ‘Gardening Australia’ and is surprisingly quite simple. It’s ordinary dish washing liquid mixed with water…or in the classic words of former presenter Peter Cundall:

“…you’ve discovered the supreme Australian pest, the harlequin bug. I call them “B doubles”, the way they get around when they’re courting. How can you kill them, because they’re covered with a kind of a wax, and that actually repels normal sprays. The answer, believe it or not, is to get the cheapest possible detergent and make a very strong solution with water and spray it on the clusters in the morning when they’re out in the sun. It gets into their breathing tubes at the sides of their, body blocks them up and they are so brilliantly dead.”

From ‘Gardening Australia’ TV show episode 39 transcript.

I prefer  to make up the solution in a small bucket and pick them off if I can so I don’t accidentally get other insects with the spray, but sometimes I will spray if they are looking to be getting really out of control. So I make sure that the detergent I am using is as environmentally friendly as possible so that any residue if I do spray is not causing further problems.

Happy gardening, I hope your good bugs and many and your pest bugs few!

Heidi

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Comments on: "The dreaded dindymus versicolour" (35)

  1. Great photos of the harlequin bugs, but I’m sorry you seem to have so many. I hope your soapy water solution helps. I occasionally mix up something similar, especially for when our aphids run amok in the greenhouse where the predatory syrphid flies can’t reach them. I don’t know if it would make a difference, as your strong soap solution might be enough, but when I make a weaker soap solution for other garden beasties, I often put a little oil (vegetable or olive oil) in the solution to help it adhere to the plant (and the bugs) better, so it doesn’t evaporate off so quickly. It seems to help to smother them.

  2. Hello Clare 🙂 Thanks for the suggestion; I might try adding a drop of oil.
    Only I’ll have to be careful not to make the same mistake as I did last year. I tried a home-made white oil spray, but was so determined to get the little beasties I didn’t pay attention to the weather conditions…I managed to fry what was left of my poor tomatoes by spraying (a little too enthusiastically) on the morning of what turned out to be a very hot day 😦

  3. These pictures reminded me of our local “Boxelder Bugs” (Boisea trivittata – in Wikipedia). I don’t know that they are as destructive, but they are creepy non-the-less. They hang out by my Rose Mallow (perennial hibiscus) and like the sunshine. Like you found, simple water & soap kill them immediately – with no adverse affect to the plant. (It still makes me shiver when I see a picture of them – uck!)

    • Hi Shyrlene, I just looked up the Boxelder bugs – wow – you can see these two bugs are related can’t you?!
      I agree, they do look kind of creepy, as are the harlequin bugs…I think it’s the way they like to cluster together that makes my skin crawl a bit. But I do like the name ‘Zug’ though!

  4. thanks for the warning – I have seen them in my garden only occasionally, but from now on I will be merciless. I love posts like these, I do want to learn about insects and am very ignorant. The worst insect I ever tangled with were weevils, I forget the exact name. I called them evil weevils and they were.

    • Hi Catmint and thanks for the lovely feedback 🙂 I know bug posts aren’t everyone’s cup off tea, but I find them fascinating! With any luck you’ll continue to only make an occasional sighting of these little horrors. Some years I have a few and some lots, sadly this is a ‘lots’ year!
      The thought of ‘evil weevils’ in the garden made me laugh, I’ll have to look out for those!

  5. Hey there, how do the plants handle the soap spray in the heat?

  6. Hi Jess, good point – I do need to be careful with it. I find if I use the soap and water without any oil added it is not such a problem, as it mostly evaporates before it can cause a problem, but I avoid spraying until evening on hot days. It’s also one of the reasons I prefer to use the ‘pick off and drop in the bucket’ method, even though catching the bugs with my hands is not really my idea of a good time!

  7. Just had a blog visitor via your last year’s post on these bugs. Curiously I’ve never seen so many again, as when I blogged about them. Not a problem in my garden as I’m still not growing food crops. The Melianthus doesn’t get cut down by frost, so I’ve taken to pruning it hard. The autumn rain should trigger lots of fresh shoots, and perhaps a few bugs.

  8. Hello Diana an sorry for the lateness of my reply! This year has been a bumper bug year here, so I put it down at least a little to that. Plus these bugs do so love a nice juicy vege patch 😦

  9. Hi, I have found these evil bugs destroying my raspberry crop. Ihave the erfect spot and the palnts weere absolutely flourishing and producing almost a handful of fruit every two days……. until the evil bugs invaded! ow I have destroyed fruit and bugs everywhere. I first sprayed with pyrethrum which worked for a couple of days (I thought) then I got really mad and sprayed with confidor (given the expert advise of my local garden shop)this definitely works IF you can manage to spray every single bug but you cannot eat the fruit for 3 weeks and after only 1 week I have more bugs than ever and am STILL throwing away my fruit. I am about to try the dishwashing liquid, oil and water mixture, I really hope this works as I am so disappointed at losing my amazing crop of fruit. Has anyone else had these bugs n raspberries? and did anything else work? I would reallu love to eat some of my crop this year!!!

    • Hello Judy and sorry about the lateness of my response! The diswashing liquid does work, but you have to be pretty relentless in spot checking, as if you miss any bugs they will start breeding again. You are better off drowning them in a bucket of the mix than spraying with it and persistence will eventually tame the population. This year I had grapevine hoppers in my raspberries rather than harlequins. Pretty devestating damage there too. Again the soap mix works, but because it is not a poison (which is my preference as I don’t want to take out the ‘good bugs’ in the crossfire) you have to be prepared to check every day or two.

  10. Hello, I have noticed these nasty little bugs in my garden. I am hoping that your solution helps. I also have another question for you. I was looking at my long stem rose bush today and noticed the tiniest little red bugs bunched up under the leaves and on the stems an all around the buds. There are groups of them I would guess in the 30-40’s 😦 how do I get rid of them?? An would you happen to have a guess on what they might be?? Thank you. Trish

  11. Hi Trish, It is quite possible that you are looking at the young of exactly the same bug. They start of as tiny red bugs.Keep and eye on them and if you see that they start developing black markings and are beginning to look more like the bugs in my third photo I’d say they are one and the same! They do like roses, particularly sucking the life out of tender new stems 😦 Flick them off into a bucket of the soapy mix, it’s more effective than spraying!

    • Hi Folks I have noticed them here in Bendigo this year in big numbers, I am not sure of the tree that we have in our back yard,it has lots of small yellow flowers on it at the moment.
      When the tree goes to seed it drops bunches of small hard black seeds about 4-5 millmeters in diameter.I will trying the soap sud potion today as we are expected to have hot weather for the next few days .Thanks Wearne

  12. […] activity going on.  When we searched the genus name provided by FlickR, we found a blog called A Year in a Gippsland Garden with an excellent first person encounter with the Australian Harlequin Bugs, here called Dindymus […]

  13. Hi, I’ve just finished cleaning these bugs out of my lounge room. Finally came across your blog. I had literally hundreds of them. I filled our bagless vacuum. the got un the house via our air conditioner. We’re next door to a Vic Uni Gardening Hub in Seddon. They have fruit trees a long the fence line. This year they didn’t pick any of the fruit or prune any of the trees. These bugs loved it. Their is now plague proportions of them. Obivously in and around the house I didn’t have to be so careful with destroying plants. But these bugs are tough. I’ve used Mortein outdoor barrier spray. Unless you spray them directly with this it’s a little ineffective. I’ve bought crawling insect indoor spray and this works well when sprayed directly. While they dislike Eucalyptus oil it isn’t as effective barrier as it is for other insects.
    I don’t know why they’ve come into the house. My theory is because it was a hot day today.
    If they come back like they were today I think I’ll have a mental breakdown. I pulled the whole lounge room apart and was at it for hours.

    • Sorry to hear about that Adam – I’ve not had them in the house!
      Is it worth talking to the people who manage the garden at VU? Managing the bugs organically might be a good learning experience for their students and if there is lots of of unattended ripening fruit around again next year, I’d imagine you will have these little horrors back again.

  14. Hey All
    gr8 to know I’m not alone in this war. Here in the Adelaide Hills we’re blessed with these critters as well RAA bugs- common name (ones always towing the other home)
    I’ve wondered if a moist/ humid environment is a deterrent as in the cooler months the bugs ‘hibernate’.
    Last year I gave up on the garden (as it was decimated) and therefore didn’t water as much. When I checked in with my neighbours who were watering a lot, I found the numbers of bugs present to be much lower. Do they prefer a dry/ dryer micro climate??
    Rusty

    • Hmmm…interesting question Rusty! I’m no expert, I only know what I see in my garden. But what I’ve seen is that while they don’t like the cold, they do seem to like juicy new stems. So my experience has been that more I water the more bugs I get. But it could be different in your area. Unless you’ve just happened to plant lots of the plants they love the most!

  15. I have these bugs in my garden at the moment.

    Could you kindly advise the mixing ratio for the dishwashing, oil and water mix.

    Also can I spray this mix directly onto tomatoe plants?

  16. No oil needed for this one Dean. Just water and cheap dish-washing detergent, but quite a bit of detergent, maybe about 20 to 25% The aim is to block the bug’s breathing tubes. Brutal but simple.
    I would suggest checking the label of the detergent you use to make sure there is no nasties in it, but I use an environmentally friendly brand that leaves no residue that would be harmful to the garden. Spraying directly on to tomato plants is fine, but I would avoid spraying on the fruit, particularly if it is sunny/hot as the detergent can make it adhere a bit. Might be better to try flicking the bugs off in to a small bucket of the solution.

  17. We have battled these bugs since moving to the Bellarine, detergent spray in one hand and the chainsaw to cull most of our native hibiscus in the other. Rampantly defoliated in summer – at one point we resorted to a systemic spray in a vain attempt to regain control -the one tree we kept has bounced back through winter to again provide the perfect combination of refuge and food source for these garden villains. In hot weather we found them sheltering under the leaf litter created by the extensive defoliation, under nearby pots and at the base of any fencing in shady spots. Tidying up and removing pots and anything else they can shelter under seemed to make a difference – have your dishwash spray ready or a bucket of soapy water to knock or brush them off into. Getting them early in the season when they first appear – ours have already well and truly started – when they’re still slow from cold and in early morning when they’re still clustered on your paling fence, is the best bet. I’ve wondered about traps – maybe there’s something in this sheltering behaviour we can exploit – has anyone tried this?

    Go well.

    • Hi Mike and thanks for stopping by 🙂 You’ve reminded me that I must cut out our native hibiscus as we’ve had exactly the same pattern with it, only we haven’t seen the little terrors return to it *yet* this year. I do like your trap idea, given how they do like to cluster under things…will have to experiment with what might make an effective lure…

  18. Have been trying hard to find the name of this bug. Finally came across your site with the info I was after. This bug has shown up in my gardens a year ago (in Tarneit). Never had them for the first 3 years living in this area, now they move along to each plant in my garden. They always start with the strawberries, if I am able to kill them off from there, the next day they will be at tomatoes, if I remove them from there they move onto the next plant. I noticed in spring they were hiding/hibernating in my Yukka leaves I have in the front of my house.

    I found another blog about with similar stories to this one. No natural predator, not even chickens will go next to them. I had a slate insect problem originally, but it seems as soon as they disappeared, these guys took over. Possibly moved them out?

    • Hi Daniel and thanks for dropping by 🙂 Thankfully I haven’t had much of a problem (so far) with these bugs this season, but it is possibly only because I’m only growing a couple of veges this year. My native hibiscus has also gone which was one of their favourite hiding spots and I’m starting to wonder how important to them it is to have an ideal host/hibernation plant…by the sounds of things it is probably just as well that I don’t have a Yukka!

  19. Benjarmen said:

    These little buggers have been eating the buttercups in mt dandenong and are now all through my veggies from beat root leaves to the rocket and kale, tomorrow is soap time for these fellas 🙂 thanks for the handy tips

  20. Thanks for the advice on the dishwashing liquid. We live in Swan Hill and I am a first time veggie gardener. I have noticed them around my capsicum seedlings but didn’t take too much notice because I was concentrating on the plague proportion earwigs the previous month. Like you said, I looked at them, and their babies, more with curiosity than alarm but one of my tomato seedlings went from hero to zero within one week recently and I put it down to the earwigs or something else. Today the harlequin bugs were all over the seedling in its death throes so I decided to do some investigating and they were also around some other tomato seedlings and especially around the capsicum bed which is now almost bare. Have started spraying with your recipe and will tackle them with the zest I applied to the earwigs.

  21. hi

    Thanks for this post been trying to find out what these bugs were called as im gardening illiterate mostly and having just started a vegie garden these things were everywhere. i tried planting flowers herbs etc to bring in some predators but no luck. Will be spraying my garden tonight when it cools down and hope for the best.

  22. Thanks for a great introduction (and fantastic quality photographs!). For ages I didn’t pay much attention to the harlequin bug outbreaks; but knowing they were a sap-sucker I did wonder about transmitting disease and so on.

    They have been very bad this year. Maybe it’s the wet summer weather we’ve had. So after finding your blog I looked up any scientific papers that seemed relevant.

    I’ll post these notes at http://astherivergoesby.tumblr.com if anyone wants to look for links to references.

    Control of mallow/hibiscus species (like the weeds that commonly grow in my lawn here in Bacchus Marsh) seems sensible, based on a paper from Latrobe University, published in the Australian Journal of Ecology in 1981. The study found that while the bugs may feed on many plants, and also carrion and are cannibals, they start the year principally in Malvaceae (mallow, hibiscus). The native hollyhock Malva Preissiana (previously called Lavatera Plebeia) is apparently their main native host plant.

    As the summer progresses and the mallows go to seed, the bugs then opportunistically move to other convenient plants. So I’d hypothesise that if the mallow weeds are controlled well in early spring, the outbreaks of the bug could be reduced later on.

    I’ll test this hypothesis next Spring! It will mean a bit of a dilemma for what to do with the beautiful native hollyhock growing in my front garden – it was the most beautiful floral display this spring just gone!

    The other possibility for control is perhaps in their dormant stage. They apparently overwinter under bark or in leaf litter and mulch, so depending on how your garden is set up, you may be able to reduce their refuges. Certainly, getting rid of mulch from your vegie garden in winter can reduce slug and snail populations, and lets the sun warm the soil, so it’s not a bad idea (if it rains a lot, your soil may get compacted though).

    For those wondering about predators, one record I could find was from the CSIRO journal Emu (“Austral Ornithology”), in 1911, which in a survey of the contents of birds’ guts/gizzards, found a D. versicolor in the gut of a fan-tailed cuckoo (Cacomantis flabelliformis). This bird (according to my bird guide) is usually found in closed forests from cape york south, and across SE Australia. Whether you can get it in your garden, and whether it will eat many of the bugs, I have no idea!

    • Thanks Ben, it was very interesting reading the additional information you found. This year is the first year in many that I haven’t noticed them…yet. But my native hibiscus is gone as are the hollyhocks. Plus I have moved my vege patch to where the duck can supervise bugs and maybe she has a taste for them after all.
      Good luck with your own efforts to control the little horrors!

  23. Thanks everyone for dropping by. I’m afraid I’m not keeping a close eye on the blog at the moment and won’t be able to reply to comments for the time being at least. But I hope the information here continues to be of help!

  24. […] you would like more information about the Harlequin beetle I found a great post by a blogger gippslandgardener I really did get a lot out of this post. It’s really is worth a read. Thanks so much […]

  25. I have these in my garden and I’ve noticed that their instars (young ones before they start mating) will over winter on certain plants. These are usually Malva (marsh mallow and hollyhock), tomatoes that we’ve been a bit slack and not removed and I noticed them (but to a lesser extent) on docks. Once I started removing any of these weeds (and old tomato plants) I noticed that their numbers suddenly crashed and have been less of a problem. Like you, I haven’t noticed anything eating them (except the odd spider) and the chooks avoid them like the plague.

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