Tiny wasp on standby to fight destructive brown stink bugs
A parasitic wasp the size of a pinhead could take down the brown marmorated stink bug.
The Environmental Protection Agency pre-approved the release of the tiny wasp earlier this year, the country’s first preemptive approval of a bio-control measure.
The wasp is one of several lines of defence against the brown marmorated stink bug (BMSB), an invasive pest which feeds on more than 300 plants and has already cut a swathe through Europe and the United States.
A 2017 report from the NZ Institute of Economic Research found that if the bug gained a foothold in New Zealand, it could cost the horticulture and arable industries $4 billion.
On Thursday more than two dozen live BMSBs were reported to have been found in a box of shoes imported into
New Zealand from EBay. The incident was reported just a week after three live and 39 dead BMSBs and 69 other regulated stink bugs were found aboard a vehicle carrier anchored off Auckland. The ship was directed to leave New Zealand waters.
Dr David Teulon, director of Better Border Biosecurity (B3), said any find of a small population of pests like the BMSB was concerning.
‘‘BMSB is a potentially very serious pest to many of our valued plant systems, both productive and natural,’’ he said.
‘‘But it is also an important ‘social’ pest, as it is known to invade dwellings in large numbers.’’
B3 is a cooperative science collaboration that researches ways to keep new pests and diseases out of New Zealand.
Teulon said the BMSB was recognised as one of the more problematic biosecurity threats the country faced.
‘‘The pre-emptive approach [to controlling it] is considered a world first, and is recognised by the international community as an example of New Zealand doing things right.’’
The wasps do not sting humans but are a natural enemy of the stink bug. The female wasp lays her eggs inside stink bug eggs, and the wasp larvae eat their way out, killing the developing stink bugs in the process.
Studies overseas have shown that the samurai wasp can destroy more than 80 per cent of stink bug eggs. If the stink bug became established in New Zealand, samurai wasps could be imported, most likely from the US.
The wasps could only be released after a stink bug invasion has been detected, and only at the location of the incursion. Any release would need Ministry for Primary Industries approval.
Teulon said the stink bug posed several unique challenges for New Zealand, including that it hid in many commodities that crossed the country’s border and was difficult to find and kill. ‘‘The current pheromone attractants are not as strong as others used in biosecurity.’’
Federated Farmers biosecurity spokeswoman Karen Williams said the latest discovery of the bugs was ‘‘very scary stuff for our nation’s growers’’.