"The stink bug season for us runs from September to April – the autumn and winter months in the northern hemisphere. That’s when the bug starts aggregating in dark sheltered places, including cargo," says MPI response adviser, Catherine Duthie.

Brown marmorated stink bug is a serious horticultural pest in the United States and is also starting to spread through Canada and parts of Europe.

Dr Duthie says MPI and industry groups have been working together to prepare for the increased risk. "A big focus has been bolstering New Zealand’s border defences. Our border team has redeployed its officers to target inspections on containers from the United States and Italy, where the bug is well-established in some areas. We know brown marmorated stink bug has been causing major problems for farmers in northern Italy, so we’ll be watching imported goods from this country very closely."

In addition, MPI has increased its surveillance of wharves and vessels, particularly ships that carry imported vehicles and machinery, and areas where cargo is held on ports. It believes the bug is most likely to establish itself in an urban setting if it gets past the border. So the ministry is running a marketing campaign to alert gardeners, city councils and other urban groups on how to recognise the bug.

"We want anyone that sees a brown marmorated stink bug to catch it and call MPI."

The ministry is also encouraging arriving air passengers to check their baggage and notify MPI if they find anything.

Dr Duthie says MPI is well prepared to handle a border incursion by the bug. "Among other things, we’ve just completed successful trials with the United States Department of Agriculture to see if detector dogs can be used to sniff out the bug in an outdoor environment. We know we can get sniffer dogs into the field at short notice if required."

She says MPI has also been developing traps and has been working to register insecticides for use against the bug should it be detected in New Zealand.

MPI border staff intercepted 406 brown marmorated stink bugs between January 2015 and April 2016.

Brown marmorated stink bug (BMSB)

• Brown marmorated stink bug is a voracious eater of horticulture produce, including apples, grapes and tomatoes; 
• A wide range of crops would be unmarketable if damaged by BMSB. Some growers in parts of the United States where the bug is established have reported crop losses of up to 95 percent;
• BMSB is resistant to many insecticides, making it difficult and expensive to control. 

When it gets cold, BMSB tends to bunch up in large numbers in dark spaces in homes and other dwellings, making it a major public nuisance.