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Black Portuguese millipedes

Agronomist, Alistair Tippett (Landmark), has reported large numbers of black Portuguese millipedes (Ommatoiulus moreletii) in canola near Anakie, in the Western district of Victoria. They are mostly being found under the residue trash in a paddock where slugs are also present. The paddock was sown to barley in 2011, and burnt several weeks prior to sowing. Alistair says canola plants are showing signs of rasping and chewing damage, although it is unclear whether this is due to the slugs or millipedes. There are also areas of the paddock where entire plants are missing.

Black Portuguese millipedes have also been reported in a more established (5-leaf) canola crop near Henty, in the Riverina district of New South Wales. Agronomist, Sandy Middleton (AGnVET), has observed very high numbers of millipedes and significant feeding damage consisting of holes in leaves, stems chewed and eaten out growing points. This paddock was also burnt prior to sowing and the seed was treated with imidacloprid. Sandy says millipedes are predominantly being found just under the surface and around any remaining trash.

Black Portuguese millipedes have a smooth, cylindrical body made up of 50 segments when fully developed. Adults are 30-45 mm long, dark grey to black in colour and have 2 pairs of legs on each body segment. When disturbed they either curl up in a tight spiral or thrash about trying to escape. Black Portuguese millipedes congregate in large numbers and are quite mobile, especially after the first rains in autumn.

In the past we have received reports of black Portuguese millipedes causing damage to young canola seedlings. However, we have also heard of many instances where high numbers of millipedes are present in a paddock but no crop damage has occurred. Feeding damage is relatively rare as millipedes predominantly live off organic matter such as leaf litter, decaying wood and fungi. A night time visit to these paddocks will help determine if the millipedes are in fact feeding on the canola plants - as millipedes are mainly active and feed at night. Understanding what is really happening within paddocks is critical before considering control options.

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