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 and where is the vegetation control zone?

MAF has established a vegetation control zone under the Biosecurity Act to limit the spread of the painted apple moth. The pest can be easily spread by moving plants they are living in so the vegetation control zone establishes a containment area that vegetation cannot be moved out of.

The vegetation control zone extends beyond areas where painted apple moths have been found and beyond the area covered by aerial operations.

A map of the vegetation control zone is now available:

  • Map of vegetation control zone - small GIF
  • Map of vegetation control zone - large JPG

Please contact the painted apple moth information line for more information.

Violating the vegetation control zone is an offence under the Biosecurity Act carrying a penalty of up to 3 months imprisonment or a fine of up to $50,000. For a corporation the penalty is a fine of up to $100,000.

Who is sampling and monitoring rivers for didymo and how and when will this be carried out?

Surveillance for didymo is ongoing and has been an important part of the response since day one. Formal surveys were first conducted in Southland and Otago regions in December 2004. This was supported by a nationwide call for all organisations regularly working or conducting research in other New Zealand rivers to keep an active look-out for signs of didymo. Since the transition from response to long term management in 2007 the responsibility for ongoing sampling and monitoring work has moved to organisations with regional responsibilities. They select the most important places for sampling in their area and decide how often to sample. Regional groups can store their sample results in the national didymo samples database (offsite link to

How do people spread Argentine ants?

Anything transported from point A to point B can potentially harbour Argentine ant nests.

Materials that are most at risk of harbouring a nest include rubbish, and garden or nursery products like potted plants, garden mulch, bark chips, and compost.

However, these ants also readily establish nests in cars, caravans, or even aircraft. And in this way can spread themselves across town, or around the country with ease.

Argentine ant infestations are frequently not detected until they have reached the stage of becoming a human nuisance. This may take two years or more. By the time they are detected, the ants are probably well established and may even have spawned sub-colonies that have hitched a lift elsewhere.

Why can’t dog tail injuries simply be treated as and when they occur in the adult dog?

Tail injuries to adult dogs can be treated, although treatment may be prolonged and there can be complications. 

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.

How long has Varroa been here?

We don't know for sure, but it was probably here for around two years before it was detected in 2000.

What is the Asian Tiger Mosquito?

The Asian Tiger Mosquito (Aedes albopictus) occurs throughout the tropics of Southeast Asia, the Northern Pacific and Indian Ocean Islands, north through China and Japan and west to Madagascar. The Mosquito has also spread to North and South America, with more recent introductions into areas within Africa, Australia, the South Pacific Islands and Europe.

Mosquitoes go through four separate and distinct stages during their life cycle: eggs, larvae, pupae (resting stage), and adults. They have an elongated proboscis (mouth piece) with which the female bites and feeds on blood.

Our mosquito identification experts use microscopes to identify physical differences to tell different species apart.

Adult Asian Tiger Mosquitoes range in size of approximately 2 mm to 10 mm and have black bodies with a conspicuous pattern of white stripes. There is a distinctive single white band (stripe) down the length of the back. There is also a native New Zealand mosquito that has white stripes, so the best indication of an Asian Tiger mosquito may be aggressive daytime biting. Adult female Asian Tiger Mosquitoes feed on humans, animals, birds and frogs.

What is the System of Equivalence for standard requirements?

The TF Gen guidance document provides ways to meet the requirements of the Standard. If the examples shown in the guidance document are not appropriate for a particular facility, then they may devise their own equivalent systems to suit their specific needs. However, any equivalence systems must meet the same biosecurity outcome as examples given, and must also be approved by MAFBNZ prior to use. If you have developed a customised system, contact your local Biosecurity Inspector who can assess whether or not it is appropriate.

What is avian influenza?

Avian Influenza is a disease of birds caused by Influenza A viruses of the family Orthomyxoviridae. Avian influenza viruses are present worldwide and numerous 'subtypes' and 'strains' exist.

Avian influenza viruses are naturally present in many species of wild birds, especially water fowl (ducks and geese). Most are harmless and do not cause disease in humans or birds.

Strains of avian influenza can be categorised as low pathogenic (LPAI) or highly pathogenic (HPAI) on the basis of the severity of clinical signs in chickens. LPAI may cause mild clinical disease in chickens, but are of no concern to human health.

Certain strains of LPAI virus have changed to become highly pathogenic avian influenza. HPAI is a severe form of the disease that spreads quickly, causing sudden death in poultry. All outbreaks of highly pathogenic avian influenza (HPAI) in birds to date have been either H5 or H7 subtype viruses (strains of LPAI viruses that have changed to become HPAI), although not all H5 and H7 subtypes cause disease. The H5N1 (Asian strain) avian influenza virus, commonly referred to as bird flu is HPAI.

What other measures will MAF be taking to stop GM from growing again in the same fields after harvesting?

MAF will include additional controls in the harvest process to minimise the probability of the formation of a self-sustaining population of GM Zea mays. Protocols covering these controls will be written and distributed to growers.

MAF will also perform follow-up visits to sites.