Millipedes belong to the subphylum Myriapoda which mean “many pairs of legs”. Also their class, Diplopoda, means “double foot” which may refer to them having two pairs of legs on each body segment.
Their colour ranges from slate-grey to black. Juveniles are light brown or grey and have stripes. Its smooth, round body is different to most Australian species which look bumpy. They are fairly quick moving and are generally found in significant numbers.
They will curl up if threatened and exude an awful smelling and distasteful liquid to deter predators.
Adult size: 20-45mm
Out and about
They are most active at night. They like moist conditions and therefore tend to stay hidden in hot dry periods coming out when it rains, particularly in spring and autumn. Native to southwest Europe, the black Portuguese millipede is now found in some Atlantic islands, South Africa and Australia. Since its introduction to Australia it has become common in the southern states.
Reproduction and Life cycle
The female will lay up to 200 tiny eggs in the soil during autumn and early winter. When the young first hatch they are legless and immobile. After about a week they develop three pairs of legs and continue to develop more legs and segments with each moult until they reach maturity. This usually takes around two years and involves 10 or 11 stages or moults after which they will moult another 5 or 6 times for another year.
To deter
To control
They are attracted to lights so best not to have lights on in seedling houses. Alternatively, a light can be used to lure them away from plants using a smooth sided box buried in the ground, flush with the surface so that the millipedes will fall into the box and be unable to get out.
There is a parasitic nematode (Rhabditis necromena) which only attacks millipedes but it can take years before millipede numbers are substantially affected.
Plants to repel
Plants to attract
Predators
Spiders / Beetles / Parasitic fly
NB. The natural predators which occur in Portugal are not found in Australia.
Why they are a Pest
They feed on fruit, roots and seedlings of melons, strawberries, tomatoes and potatoes. Generally, if they are not in large numbers, they don’t do a lot of damage and can help with decomposition of organic matter.
