New Zealand scientists working to stop spread of brown marmorated stink bugs

Kiwi scientists are working in Italy to try and find ways to stop the spread of the "serious super pest" brown marmorated stink bug. 

The pests are not established here, but options for controlling them if we faced an outbreak include releasing another insect -  the pinhead-sized samurai wasp. 

Across northern Italy, brown marmorated stink bugs are causing havoc.

Outside of their native Asia, they are running rampant and causing widespread damage to fruits and vegetables in summer and invading homes during winter.

And back in New Zealand, scientists are watching closely.

"Every year we are on a little higher alert and this is because the population is certainly expanding throughout Europe," Dr Cath Duthie from the Ministry for Primary Industries (MPI) says.

"The numbers are growing. We obviously have an increase in trade and tourists year-on-year, so there's increasing pressure on our borders."

Such is the threat to New Zealand's $9 billion horticulture industry, scientists from organisations including MPI and Plant & Food are working overseas to try and understand the threat.

"It is very much a serious super pest. I would call this a super pest because of the scale of the damage," Dr Max Suckling from Plant & Food Research says.

He has been working in Trentino during the Italian summer on new traps to improve the chances of detecting an incursion of stink bugs if they ever arrive in New Zealand.

"One of the traps that we've been working on most recently is a live trap. And it's a little bit like a fish trap, basically.

"It generates a pheromone plume. And the bugs are going into that trap in much higher numbers than they have been to the standard sticky panel."

On the farms, netting is proving effective in some situations but it isn't possible to net all types of crops.

At Lara Maistrello's laboratory in Reggio Emilia, northern Italy, the stink bug expert is pinning her hopes on the tiny samurai wasp being an effective control because it lays its eggs inside those of the stink bug.

"Like the movie Alien, pretty much, that's what they do. They lay eggs inside eggs of the other species and then they will develop."

The samurai wasp has been approved for release in New Zealand if the stink bugs arrive, although scientists believe it's not so much if, but when.

"I'm really hoping this isn't the year, but we can only really get away with it for so long before we have to respond to bugs out in the environment," Dr Duthie says.

In the meantime, vigilance is key. So if you see one of the critters in the shoes you ordered from eBay, make sure to let someone know.