Helen McKerralHow to protect soft fruit from millipedes

Ah, the luscious taste of strawberries straight from the garden – YUM! Unless they have a millipede inside: then it’s definitely BLECCCHHH! Millipedes aren’t toxic but they produce a highly irritant fluid when handled – or chewed! – that’s so foul-tasting and -smelling that many chickens won’t touch them, although apparently ducks will. Unfortunately, any duck that eats your millipedes will also eat everything else in your vegie garden!

There will be a foul-tasting millipede inside this strawberry

There will be a foul-tasting millipede inside this strawberry

Portuguese Millipedes snuck into Port Lincoln in South Australia in the early 1950s, and have since spread throughout Southern Australia. They’re herbivorous and do little damage to ornamental gardens, but damage seedlings and soft fruit in the vegie patch. Although they supposedly only attack fruit (such as strawberries) and root vegetables (potatoes, carrots) at ground level, the Olympians in my garden happily climb raspberry canes and two-metre (6 foot) high tomato vines. Tomatoes attacked by millipedes look like something out of a horror movie. Double blecchhh!

BLECH! The 'horror movie' of millipedes through your tomatoes!

Double BLECCHH! The ‘horror movie’ of millipedes through your tomatoes!

When they’re in plague proportions, as they were when we moved into our new home in the mid 1980s, they enter the house, climbing walls and ceilings, and falling onto your face as you sleep, or crunching underfoot during nocturnal loo visits. The recommended treatment at the time (and, surprisingly, one that’s still recommended) was to spray carbaryl around the walls of the house to kill them before they enter. Unfortunately, carbaryl also seemed to attract them, so every morning I swept literally a bucketful of dead millipedes from the paths around the house. In any case, we were so dismayed by the many other dead insects and spiders that we never again used this non-selective insecticide.

Millipedes climb my 2m high tomato vines

Olympian millipedes climb my 2m high tomato vines

Another time, I spread blue snailbait (methiocarb) widely in the garden beds around the house, and this was very effective, but I only did this once as well, because of the potential to poison non-target animals such as frogs, skinks and birds. I now sparingly use Multigard Snail Bait in the vegie patch, a very low-toxicity, more target-specific iron EDTA complex (iron chelate) bait that won’t affect worms, beneficial insects and animals – including pets – if used as directed.

In the late 80s, a parasitic nematode was distributed in my local area and, since then, numbers have never reached the same plague proportions. With better door seals and light-excluding curtains, we no longer get many in the house, even in autumn when numbers peak, and there are many other ways to combat them.

Strawberries on the ground attract millipedes

Strawberries on the ground attract millipedes

Outdoors, however, many of the physical controls (eg removing organic matter and mulch) are counterproductive. Most crops are safe in summer, but there are still enough millipedes around to damage susceptible plants like strawberries, especially after rain or in heavily irrigated crops where soil and mulch stay permanently moist. Knowing how attractive strawberries are to millipedes, I wonder about the chemicals that commercial growers in the Adelaide Hills use to control them.

Unsurprisingly, many Hills gardeners I know have given up on growing strawberries, but others have come up with clever ways to thwart the little buggers – one gardener told me he simply picks the strawberries just before they’re ready to eat, and ripens them indoors!

Diatomaceous earth is an effective, albeit expensive and time-consuming organic product to reapply. I use diatomaceous earth for seedlings, but wouldn’t use it in an extensive strawberry patch.

The strawberry plants in a tall pot around the fig have mostly escaped millipede damage

The strawberry plants in a tall pot around the fig have mostly escaped millipede damage

A light trap is another good idea – you can make your own, or buy one. I’ve not used one but it seems worth a try, so I’ll report back and let you know.

The most common way to exclude pests is to raise plants so the millipedes can’t reach them. One gardener grows them in an old bathtub because the sides are too slippery for them to scale, and even the plants I put around my fig tree in a 90 cm (3 foot) tall pot have largely (but not entirely) escaped the pest. My strawberry planters fared better than plants grown in the ground, but not as well as those in the tall pot.

Strawberry planters still have some fruit hanging too close to the ground

Strawberry planters still have some fruit hanging too close to the ground

Another gardener told me she grows them in planters, propped on upturned plastic pots in a water moat. Hanging baskets are effective too, as well as numerous variations on the PVC hanging planters either: vertical (Backyard Gardening, Handimania), or horizontal.

When you google, you’ll find lots of ingenious containers adapted for strawberry growing that would exclude millipedes, ranging from 44-gallon drums to woven fabric, timber, terracotta and almost any other combination of shape, size and material you can dream up !

My newly built strawberry tree made from sewer pipe

My newly built strawberry tree made from Y junction sewer pipes

The strawberries in my strawberry tree are thriving

The strawberries in my strawberry tree are thriving

So I thought I’d try a strawberry tree combining 100mm (4 inch) sewer pipe Y-junctions, plus pipe to make a 100mm (4 inch) section between each Y for a bigger volume of soil. It was less than one hour’s work to assemble because I didn’t glue the sections together: if this one worked, I planned to relocate it and build several more to create a little forest of them in bright primary colours. I hammered two short star droppers into the ground, slid the tree onto it and spray painted it red. When it was dry, I filled with good quality, dampened potting mix, planting the runners from the bottom up as I went. Then I wound 4mm irrigation line up the tree, placing a junction at each opening with a dripper. This was connected to an irrigation station watering once every three days – not quite enough in very hot weather, but adequate. To pretty it up, I paved a circle around the base. It turned out very stable with no chance of toppling.

Lots of undamaged strawberries ready to harvest

Lots of undamaged strawberries ready to harvest

I fertilised regularly with fish emulsion (Powerfeed for vegies) and Seasol and harvested the best and cleanest crop of strawberries I’ve ever raised. Only the strawberries on the lowest plant were attacked by millipedes, and that was because the lowest Y was too close to the ground. As the sections aren’t glued, I can simply swap the bottom piece of pipe for a longer one.

I also read online that the strawberry plants will need replacing more often than ones in the ground, but I’ll try them for one more year and see how they go with my fertilising regime.

There's nothing like home-grown strawberries

There’s nothing like home-grown strawberries

To sum up: the tree worked very well, but 150mm (6 inch) pipe would have been even better than 100mm (4 inch). However, the 100mm was available at my place of work (ie reasonably priced with staff discount; a 150mm pipe would only require holes drilling and would probably be cheaper). I’m also tempted to try some of the horizontal sewer pipe planters, which I could suspend from the cypress pine frames in the garden.

Yum, fresh strawberries from the garden

Yum, fresh strawberries from the garden

So for gardeners plagued by millipedes: don’t give up on your strawberries – there are plenty of container options around!

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Helen McKerral

About Helen McKerral

Horticultural journalist, photographer, contributor to many garden magazines, and author of 'Gardening on a Shoestring'. Adelaide Hills, South Australia

9 thoughts on “How to protect soft fruit from millipedes

  1. JenniP on said:

    Really feel for you with those millipedes; we have them storm our place inside and out, especially in Autumn. Some seasons are worse than others. How fabulously clever is your Strawberry Tree! I think it could be the perfect solution to my biggest strawberry thief – skinks! We’ve always known how much Stumpy Tailed lizards love strawberries & got our kids to make a line of small strawberry slices on the lawn and watch with wonder as the big lizard chomped their way across the yard. We’d suspected for a while we had strawberry-thieving skinks when they always were dashing out of the strawberry patch but one day I caught one red-handed almost literally! Little guy had his choppers around a strawberry about 20 times bigger than his own head, running awkwardly through the garden like he’d just discovered treasure!

    • helen mckerral on said:

      I have skinks in my garden too, but I figure they eat so many bugs I don’t mind if they pinch a few berries!

  2. I think if I saw a strawberry invaded by millipedes like your photo of them through the tomato, I’m not sure I could ever eat one again! Stomach turning. The few strawberry plants I have are also constantly raided by skinks so your pipe strawberry tree would be an attractive solution for me too.

    • helen mckerral on said:

      Yes, should work for skinks either. You can paint the trees any colour you like, but gloss is best because it’s slippery. I reckon a little forest of primary-coloured trees – each a different height – will make a fun focal point, and I can put them somewhere root competition from trees precludes growing a crop in the ground.

  3. Graeme on said:

    Hey Helen.
    Im at Ashton so i know what you are on about.

    I built a mud brick house, i was almost ready to sell up they got to me that much.
    I now use a product called Coopex it works a treat as a perimeter spray around the house.

    • helen mckerral on said:

      Yes, Coopex is a non-specific residual pesticide. It kills all insects and spiders, and is very long-lasting. We sell a lot of it in my local nursery every autumn but I wouldn’t use it in my garden… precisely because it is non-specific and residual! As I said, I no longer have the numbers that existed previously but, if I did, I’d invest in buying the parasitic nematodes and introducing them to the garden. The nematodes only establish if you have large numbers (plague) proportions of millipedes and are very expensive but IMO it would be an ideal solution: http://www.bugcentral.com.au/Shop/Products/rvdsfpid/20

  4. Rosemary on said:

    I have a plague of millipedes in my mulberry tree. Almost every ripe fruit has been half- or fully-sucked dry by a millipede, often still attached to the fruit. Any suggestions on how to get rid of them are most welcome.

    • helen mckerral on said:

      That’s a tricky one, Rosemary – they don’t get to my Shahtoot mulberry in a pot, so they must be climbing the trunk of your tree. Here are some ideas, but I have no idea whether they’ll work! Prevention is going to be kep, I think – once the critters are up there, it’s too late. get back to me if you have success, though now the millipedes are in the tree, it’s probably too late for this season.

      You could try sticky banding the trunk with horticultural glue (“Trappit”) BEFORE the fruit ripens (trim any low hanging branches whose twigs reach the ground).

      Another thing worth trying is diatomaceous earth spread around the base of the tree.

      Millipedes get some of my autumn raspberry harvest when it’s cool and moist, but not the earlier ones when the weather is still dry. I’m not certain where you are in Oz, but watering with shrubblers rather than overhead sprinklers might discourage the millipedes from ascending into a drier canopy.

      Removing the mulch (where millipedes breed) underneath the tree might help, but millipedes travel long distances so that might not compensate for the disadvantage of reduced soil fertility.

      By all accounts the light traps I mentioned are worth a try.

      • Rosemary on said:

        I should have added that I’m in Sydney. The mini-heatwave we just had seems to have killed off the millipedes. I can’t find a single one (dead or alive). The mulberries that are now ripening are nicely plump.

        Next year I might not be so lucky. A mild, wet Spring could mean a whole crop of berries gets taken by millipedes.

        Thank you so much for your suggestions. Come next Spring, before the fruit ripens, I’ll apply a pre-emptive band of horticultural glue around the trunk and maintain a good layer of food-grade diatomaceous earth around the base.

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