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.

What does 'companion animal' mean in the Animal Welfare (Leg-hold Traps) Order?

An 'animal' (as defined by the Animal Welfare Act 1999) that is

    (a) Not a 'wild animal' (as defined by the Animal Welfare Act) or a 'pest' (as defined by the Animal Welfare Act) and that
    (b) lives with humans as a companion and is dependent on humans for its welfare.

Please note this information is provided by way of general guidance only and does not constitute legal advice. Parties are advised to seek independent legal advice in relation to particular fact situations.

Note: In the Animal Welfare Act 1999 (offsite link to (section 2):

"Animal" -

    (a) Means any live member of the animal kingdom that is -
    (i) A mammal; or
    (ii) A bird; or
    (iii) A reptile; or
    (iv) An amphibian; or
    (v) A fish (bony or cartilaginous); or
    (vi) Any octopus, squid, crab, lobster, or crayfish (including freshwater crayfish); or
    (vii) Any other member of the animal kingdom which is declared from time to time by the Governor-General, by Order in Council, to be an animal for the purposes of this Act;
    (b) Includes any mammalian foetus, or any avian or reptilian pre-hatched young, that is in the last half of its period of gestation or development; and
    (c) Includes any marsupial pouch young; but
    (d) Does not include -
    (i)A human being; or
    (ii) Except as provided in paragraph (b) or paragraph (c) of this definition, any animal in the pre-natal, pre-hatched, larval, or other such developmental stage.

"Pest" means -

    (a) Any animal in a wild state that, subject to subsection (2), the Minister of Conservation declares, by notice in the Gazette, to be a pest for the purposes of this Act:
    (b) Any member of the family Mustelidae (except where held under a licence under regulations made under the Wildlife Act 1953 (offsite link to
    (c) Any feral cat:
    (d) Any feral dog:
    (e) Any feral rodent:
    (f) Any feral rabbit:
    (g) Any feral hare:
    (h) Any grass carp:
    (i) Any Koi or European carp:
    (j) Any silver carp:
    (k) Any mosquito fish:
    (l) Any animal in a wild state that is a pest or unwanted organism within the meaning of the Biosecurity Act 1993 (offsite link to

"Wild animal" has the meaning given to it by section 2(1) of the Wild Animal Control Act 1977 (offsite link to

What restrictions have been put in place?

MPI has issued a Controlled Area Notice. This is a set of restrictions that apply within a defined area – in this case, a circle 1.5 kilometres out from the location of the fruit fly find. A full map of the area and list of street addresses that make up the boundary is on the MPI website:

Within this Controlled area there are two zones – Zone A is the area closest to the find and goes out to 200 metres. Zone B is beyond that out to 1.5 km.

If you live in Zone A, you are required not to move any whole fresh fruit or vegetables from your property.

If your home is in Zone B you can move whole fresh fruit and vegetables into or within the defined Controlled Area but not outside of it.

Importantly, anyone living in the whole Controlled Area is allowed to move any food products into the area from outside.

Full information on the Controlled Area is on the website.

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.