MPI staff intercept thousands of unwanted pests in Canterbury
An ant species described as silently aggressive towards humans with an appetite for rubber and plastic has been intercepted twice this year by biosecurity staff in Canterbury.
The Singapore ant, or destructive trailing ant, was one of thousands of unwanted visitors detected in the region, including venomous spiders, a scorpion and fruit flies capable of causing untold damage to the horticultural sector.
Figures released under the Official Information Act showed Ministry for Primary Industries (MPI) staff made a total of 855 interceptions in Canterbury in the year to September.
The interceptions, carried out at a rate of about three a day, resulted in the detection of more than 2700 spiders, mites, insects, snails and other pests from 42 different countries.
They were made by MPI inspectors at Christchurch Airport, Lyttelton Port and at approved transitional facilities, often located at importers’ premises.
MPI border clearance manager central and southern Andrew Spelman said given the rise in trade and growing tourism numbers, there was growing pressure to keep pests from becoming established in New Zealand.
He singled out the detection of oriental fruit fly larvae – in both instances discovered in mangoes carried by passengers travelling from India – as the most significant biosecurity save.
‘‘If these live larvae were able to get out and into the right environment and they became established, the implications for our wider horticultural industry would be huge,’’ Spelman said.
In 2015, MPI spent $15.7 million eradicating 14 Queensland fruit flies discovered in the Auckland suburb of Grey Lynn – spending more than $1m per fly.
Five destructive trailing ants were discovered on an apple carried by a passenger from Australia in July, while another six were discovered on dried fish carried by a passenger from Fiji in March.
The invasive species, which was not established in New Zealand, was known to bite sleeping babies and children, and its practice of chewing through substances like rubber and plastic had caused electrical faults and fires.
In 2005, an Auckland man returning from Fiji discovered a colony of 50 ants in an iPod, which he was advised to freeze in order to kill the pests.
Spelman said another notable biosecurity threat detected in Canterbury was the brown marmorated stink bug, which had the potential to devastate the horticultural and viticultural industries.
Single stink bugs and groups of the invasive pest were detected 17 times over the course of the year, though all but one were dead on arrival.
The bugs arrived in New Zealand on shipments from Italy and the United States, where it had caused millions of dollars of damage to crops since it was got into the country in the 1990s.
‘‘It’s a huge nuisance pest as well for people living in suburban areas,’’ Spelman said.
Aside from the eradication cost, both fruit flies and the stink bugs would cost New Zealand in terms of market access and the increased use of pesticides, he said.
Four highly-venomous redback spiders from Australia were also discovered in Canterbury this year, as was a marbled scorpion – a small species that grew to about 3 centimetres in length.
Ecuador was the single largest country of origin for intercepts in Canterbury, making up 284 of the 855 intercepts this year, and 308 of the 905 made in 2016.