Key Takeaways
- Historical newspaper accounts from the 1940s describe severe black Portuguese millipede invasions in Hawke’s Bay, Tauranga and Wellington’s Kilbirnie suburb, with residents resorting to homemade poisons and potato‑slice traps.
- Early control methods relied on toxic mixtures such as bran, Paris Green (copper‑arsenic insecticide), molasses and water, or “potato slices impregnated with Paris Green.”
- In recent years, Wellington’s south‑coast suburbs (e.g., Ōwhiro Bay) have experienced recurring spring‑and‑autumn swarms that infiltrate homes, beds and even pets, prompting public pleas for assistance.
- The Ministry for Primary Industries classifies the Portuguese millipede as a nuisance species, meaning it is not subject to official pest‑control monitoring or eradication programmes.
- Research led by Victoria University entomologist Professor Phil Lester is investigating whether historic boom‑and‑bust cycles could reveal natural enemies (parasites or pathogens) that might be used as biocontrol agents in Wellington.
Historical millipede reports in Hawke’s Bay, Tauranga and Kilbirnie
More than 75 years ago, newspapers such as the Hawke’s Bay Herald‑Tribune, the Evening Post and the Bay of Plenty Times published vivid descriptions of black, worm‑like creatures about two inches long, covered in hundreds of hair‑like legs, crawling up walls, dropping into food and creating general havoc inside homes. Residents of Napier, Tauranga and Wellington’s Kilbirnie suburb complained in spring and autumn of “sinister‑looking” millipedes invading beds, lounges and even the backs of hotel premises, prompting frantic attempts to keep them out. These archival accounts provide a striking parallel to the modern millipede upsurge reported by Wellingtonians today.
Early control attempts: Paris Green, bran mixtures and potato slices
Faced with overwhelming numbers, households turned to improvised chemical remedies. A 1947 Evening Post article quoted a Kilbirnie resident who lamented, “All you can do is sit and watch the invasion,” while noting that “every handful of soil yields its quota.” The Bay of Plenty Times recommended dusting a mixture of bran, Paris Green (a highly toxic copper‑arsenic insecticide), molasses and water under houses and along walls wherever millipedes were troublesome. Similarly, the Hawke’s Bay Herald‑Tribune suggested placing potato slices “impregnated with Paris Green” as a bait‑trap. These approaches reflected the limited pest‑management tools available at the time and underscored the desperation of affected communities.
Recent Wellington infestations and resident experiences
Today, the same black Portuguese millipedes appear to be thriving along Wellington’s southern coastline. Ōwhiro Bay resident Chris Picking told RNZ that he has found the creatures “in the lounge, in the bed, crawling on the dog, hanging from the walls and the ceiling,” even waking up with one on his face. In March, another local described the scene as “less concrete, more millipedes,” attributing the surge to recent rainfall that drives the arthropods out of the soil. The insects are most noticeable in spring and autumn, forming dense swarms that infiltrate homes despite residents’ best efforts to seal gaps and clean up debris.
Official stance: MPI classification as nuisance species
The Ministry for Primary Industries (MPI) lists the Portuguese millipede as a nuisance species rather than a regulated pest. Consequently, MPI does not track population numbers, nor does it implement official control or eradication programmes. This classification means that local councils and households must rely on ad‑hoc measures and community‑driven initiatives when infestations become problematic. The lack of systematic monitoring also makes it difficult to confirm whether historic newspaper references from the 1940s pertain to the same species now troubling Wellington.
Community responses: pleas, public meetings, advisory group
Frustrated by the recurring invasions, Wellingtonians have called on authorities for help, organised public meetings, and supported the formation of an advisory group tasked with investigating ways to suppress millipede numbers. Residents have shared anecdotes of millipedes appearing in food stores, bedding and even on pets, underscoring the need for coordinated action. The advisory group brings together representatives from Greater Wellington Regional Council, Wellington City Council, mana whenua, and interested citizens to evaluate both traditional and novel control strategies, while also documenting the timing and magnitude of outbreaks.
Research on biological control: parasitic nematode trials
Professor Phil Lester of Victoria University has been leading efforts to identify a sustainable biological control. In early trials, his team applied the microscopic soil nematode Steinernema feltia—a naturally occurring organism known to infect certain insect pests—around infested properties. However, Lester reported that the nematode proved ineffective at reducing Portuguese millipede numbers under field conditions. Despite this setback, the negative result refined the research focus, prompting investigators to explore other potential pathogens or parasites that might specifically target the millipede without harming non‑target species.
Historic accounts sparking new research: boom‑and‑bust hypothesis
Lester notes a remarkable similarity between the 1940s newspaper depictions and present‑day observations: black millipedes climbing walls, appearing twice yearly (spring and autumn), and overwhelming residents. He hypothesises that the historical populations may have experienced a classic “boom‑and‑bust” cycle, wherein a sudden increase was followed by a rapid decline, possibly due to a natural enemy that eventually caught up with the pest. Because newspapers rarely report when a problem disappears, the exact timing of past declines remains obscure, but the pattern offers hope that a similar collapse could occur—or be induced—in Wellington today.
Planned fieldwork in Tauranga to find natural enemies
To test the boom‑and‑bust hypothesis, one of Lester’s research students will travel to Tauranga this summer, funded by contributions from Greater Wellington Regional Council and Wellington City Council. The fieldwork aims to locate any remaining Portuguese millipede populations in the Bay of Plenty, collect specimens, and screen them for associated parasites, fungi, or bacteria. Identifying a viable natural enemy would allow researchers to assess its safety and efficacy before considering a controlled release in Wellington’s affected suburbs.
Implications and hope for Wellington residents
While the search for a biocontrol solution continues, the convergence of historical evidence and modern scientific inquiry provides a pragmatic roadmap for managing the millipede nuisance. If a specific pathogen or parasite responsible for past population crashes can be identified and safely introduced, Wellingtonians might finally see a lasting reduction in the spring‑and‑autumn swarms that have disrupted homes and daily life. Until then, community vigilance—sealing entry points, reducing moist habitats, and reporting outbreaks—remains the best defence against these persistent, many‑legged invaders.
