Frequently Asked Questions

Could didymo spread to lakes throughout New Zealand?

Yes. Although didymo prefers a river environment with clear water flowing over stable substrate at depths sufficient for light penetration to drive photosynthesis, blooms have been found in South Island Lakes. Lake Wakatipu, for example, contains visible didymo on some parts of the lake shore.

What does the painted apple moth look like?

The painted apple moth is recognisable once you know what to look for.

There are five stages in the painted apple moth life cycle -- egg mass, larvae, pre-pupae, pupae (cocoon), and adult moths -- and the pest looks quite different at each stage. The painted apple moth is most distinctive in the larva (caterpillar) stage, when it is brightly coloured, hairy and easily recognised by the tufts of hair on its back. (No native caterpillars are hairy like the painted apple moth.)

Isn't didymo just about the South Island Rivers?

No it's about protecting all of our waterways. To date didymo has not been detected in the North Island; however people still need to Check, Clean, Dry to ensure rivers do not become affected.

What is the National Pest Plant Accord?

The National Pest Plant Accord (the Accord), developed in 2001, is a cooperative agreement between the Nursery and Garden Industry Association, regional councils and government departments with biosecurity responsibilities.

It identifies plants that are unwanted organisms under the Biosecurity Act 1993. These plants cannot be sold, propagated or distributed in New Zealand.

The Accord is not a pest management strategy. It is a non-statutory agreement between member parties. The process followed to establish and review the Accord is very different and completely separate from processes to establish and review pest management strategies.

How far can Foot and Mouth Disease travel by air?

It is generally accepted that maximum aerosol spread is 10 km over land (up to 60 km suspected) and up to 250 km over water. Concentrations of pigs can generate virus aerosols (plumes) over considerable distance if environmental conditions are suitable- high humidity, cool ambient temperature. Airborne transmission from cattle and sheep can not be shown experimentally to occur over distances in excess of approximately 3 km. Although occasionally dramatic, plumes are FMD strain specific and may not be important in disease spread. Infected animals and animal products are by far the important source of new infections.

How do Argentine ants invade an area?

Argentine ants invade and colonise an area in two ways: budding and jump dispersal.


Unlike many other ants, Argentine ant queens do not go on nuptial flights, and so form new nests within ant-walking distance of the old nest. After mating, a young queen will simply walk away with some workers, and establish a new nest nearby. Left to themselves, colonies would increase by little more than 200 meters/year.

Jump dispersal

However, young queens will readily ‘bud off’ with a few workers and establish their nests in nearby vehicles, planter pots or wheelie bins. This done, they could end up anywhere.

This ability to ‘hitch’ a lift with humans makes the Argentine ant so challenging to control. And as these ants produce around ten times more queens than other species, the challenge is magnified.

Human-mediated dispersal within suburbs across a city, and between neighbouring towns is essentially creating a large number of small ant populations throughout New Zealand, and these are likely to act as centres for further expansion.

My business has lots of daily foot traffic. Do I need to maintain a visitors record?

Depending on the facility and if risk goods are present:

If a facility is able to control access (eg customer and couriers are coming to one area to pick-up and drop-off items) then a visitors book might not be necessary.

In general, there should be no public access where uncleared risk goods are held.

Where do the restrictions apply?

Refer to the map and list of streets on the website as above.

Who decides what happens to the non-compliant wood packaging?

The importer will be given a choice of treatment, reshipment or destruction of any non-compliant wood packaging. The final decision will rest with MPI.

Could GM lucerne affect lucerne plants in New Zealand?

In the US, genetically modified lucerne could cross-pollinate with non-GM lucerne, and the modified traits may be inherited by the next generation.  Lucerne is a perennial species and feral plants grow along field edges and roadsides in the main seed production areas in the US. Consequently, wild plants containing GM genes may persist in these environments.

Little is known about the potential for persistence of these GMOs in the New Zealand environment. However, GM lucerne is not approved by the Environmental Risk Management Authority (ERMA New Zealand) for release into the New Zealand environment.