A stinky threat

The brown marmorated stink bug (BMSB) is listed as one of the horticultural industry's top six pests of concern.

While it has not established itself, there are concerns it could easily be brought into the country from places where it is already making a nuisance of itself.

What is the brown marmorated stink bug?

The adult bugs are approximately 1.7cm long, with a distinctive brown "shield" shape with a white band around the edges. They lay light green eggs (20 – 30 a time) on the underside of leaves. Thought to originate in Asia, the BMSB is found in large numbers in China, Japan and Korea. In the late 1990s it was discovered in the United States and now is present in more than 35 states. It has spread into Canada and a number of European countries have also confirmed it is present.

It feeds on a host of plants, from apples to citrus, figs to grapes, and is a pest not only to those in the agriculture sector, but also to home gardeners.

It gets its name from the smell it emits when disturbed or crushed – a particularly offensive odour, that while not a danger to human health, is described as being very unpleasant. The bugs hibernate over winter in large numbers, often in buildings or houses.

In terms of food, the bugs feed on more than 300 hosts, primarily fruit trees and woody ornamentals and field crops.

Why should the wine industry be concerned?

Grapes are a food of choice for BMSB's and their munching causes damage to the berries themselves – opening the fruit up to disease risk. But what could be worse, is the impact of these bugs being caught up with fruit at vintage. Given the odour they produce when crushed, the risk of wine taint is high.

How could they get here?

BMSB's are often referred to as the classic hitchhiker. They are easily transported in suitcases or shipping containers. In recent years a number of bugs have been discovered at the border, hitching a ride in cars that had been transported from the US. In response, MPI now demands that all vehicles coming out of the States must be heat treated or fumigated before coming to New Zealand.

"In previous years MPI biosecurity staff have found increasing numbers of brown marmorated stink bug during border inspections of vehicles arriving from the US," Andrew Spelman, MPI's Border Clearance Manager, Central and South said.

"The new rules will minimize the risk of stink bugs establishing in New Zealand well before the imported vehicles reach New Zealand."

How would New Zealand deal with BMSB?

That is the 64 million dollar question, given the bugs can rapidly increase in population and are hard to eradicate. Jim Walker from Plant & Food, Hawke's Bay gave a rundown on the top threats to our wine industry a few years ago. Regarding the BMSB he said it would be a tough assignment to get rid of them if they became established.

"In apples in the US, up to 13 pyrethroid insecticides are required to control this.
And even with those 13 treatments, there was 10 percent fruit
damage. (Controlling it) has completely destroyed IPM programmes."

Imagine the impact of that on the New Zealand wine industry and our sustainability programmes.

What can I do?

Basically, be on the lookout for anything that may be a BMSB. MPI is encouraging individuals in all walks of life to be alert to any unusual insect they may come across. Their advice is to photograph it, or if possible catch and contain it and make contact with MPI immediately. 0800 80 99 66.

And if you are travelling in one of the countries where BMSB is prevalent, ensure you double check luggage to ensure there are no nasty hitchhikers coming home with you.