Source: Radio New Zealand
A portuguese millipede. RNZ/Mary Argue
A reinfestation of invasive millipedes, crawling out of the soil and into homes, is sending residents of Wellington’s south coast to arm themselves against the bugs.
The alarm was sounded about the portuguese millipede almost a year ago, with stories of people finding hundreds of the scaly black creatures outside or inside bags, shoes and even beds.
Since then, the Ministry for Primary Industries (MPI) has identified the species in New Plymouth and Nelson – and while it is considered a nuisance, it’s not classified as a pest species and doesn’t meet the threshold for official control measures.
However residents hope to fight back, and are pinning their hopes on a tiny parasitic worm to suppress millipede numbers.
The microscopic nematode wriggles inside its host, where it reproduces. Eventually the nematode offspring become so numerous they burst out of the host’s body, killing it.
A newcomer to Ōwhiro Bay told RNZ he planned to unleash an “aggressive” species of the nematode Heterorhabditis bacteriophora, in addition to barrier sprays and insecticides.
“At this point there’s less concrete more millipedes as I step out of the house. They’re just pouring out of the soil – [it’s] probably got to do with the [recent] rainfall.
“It’s essentially like a millipede graveyard right now.”
He said he was aware of the millipedes before he moved, so was prepared, but the “volume, and the speed” of their emergence was “alarming”.
He hoped his experiment could potentially benefit others and if successful, “nip the problem in the bud”.
A trial of the nematode Steinernema feltiae as a biocontrol agent for the millipede is currently underway at Victoria University – results are expected in a few weeks’ time, but those plagued by the millipedes aren’t waiting.
Another Ōwhiro Bay resident, who had already sprayed the species of microscopic worm told RNZ their place was one of several houses on the street planning to use it.
“We … haven’t seen any effect yet. But that’s to be expected – it’s a long term thing.”
They said the millipedes were already appearing as numbers tended to surge in autumn and spring.
“They’ve started turning up – you’ll see 10, then the next day you’ll see 20, 30, and then before you know it, they’re just … everywhere.
“If I actually counted them up there’d be a couple of hundred outside and then maybe 10 or 20 inside.
“I’m prepared that they’re going to get worse for a while, before they get better.”
Sign up for Ngā Pitopito Kōrero, a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand