Biosecurity is the process of detecting and controlling unwanted crop weeds, pests and diseases. Agriculture and the natural environment are very important to New Zealand’s economy. We have a unique but fragile natural ecosystem, which developed without many of the pests that are common elsewhere in the world. Being a remote group of islands, we can potentially prevent entry of unwanted pests and avoid problems associated with damaging pests and diseases.

Animals and plants that are not pests in another country may become a problem if they are released into another environment. Humans settling in New Zealand have brought with them plants and animals that are not native, which have had a very damaging impact on the environment. For example, early European settlers brought with them rabbits for meat. With no natural predators, rabbits were able to quickly breed to very high numbers. Stoats and ferrets were then introduced to kill rabbits, but they also killed native birds – now they have to be trapped to prevent kiwi and other birds from extinction. A plant or animal that is introduced to a new environment where it has no competitors may be able to rapidly take over and be very difficult to remove once established.

Biosecurity risks

New Zealand is in the fortunate position of being free of most disease-carrying mosquitoes, and serious animal diseases such as rabies, scrapie, foot and mouth disease and BSE (mad cow disease).

However, pests and diseases like these pose serious threats to our economy, environment, health and cultural identity. An outbreak of a disease in livestock, such as foot and mouth disease, could cost the economy $10 billion. Thousands of jobs would be put at risk, and the economy would take years to recover. New Zealand’s natural habitats are also important for tourism, fishing and recreation but are at risk from plants and animals that might thrive and push out native species.

There are biosecurity threats from:

  • invasive plants (weeds)
  • diseases of plants (fungi, viruses and insects)
  • diseases of bees (varroa mites)
  • risks to the marine or freshwater environment (starfish larvae in ship ballast, didymo)
  • risks to native ecosystems (brush-tailed possum, stoats, introduced plants
  • diseases of animals (mad cow disease, foot and mouth disease).

Biosecurity in practice

For most people, the most obvious example of biosecurity activity is the specially trained beagles that are used at New Zealand airports to detect foods carried by passengers that may have a biosecurity risk. By bringing in food from overseas, you may also be bringing in any diseases or insects that live in that food.

Four main organisations are involved in biosecurity:

  • Ministry of Agriculture and Forestry (MAF)
  • Department of Conservation (DOC)
  • Ministry of Fisheries (MFish)
  • Ministry of Health (MOH).

Preventing pests

It can be very difficult to eliminate an unwanted pest species once it is in the environment, so it is preferable to prevent pests entering the country in the first place. Biosecurity checks carried out by Customs staff at ports and airports are therefore very important. Passengers arriving at New Zealand airports and ports are checked for fruit or fresh foods that may bring with them plant insects or diseases. Boats carrying cargo are checked carefully by Customs officials to make sure there are no unwanted stowaways in the form of rats or insects.

New Zealand is unique in being free from certain diseases of livestock that are common elsewhere, and maintaining this disease-free status is important to the value of New Zealand produce. The transport of pets and livestock is very carefully controlled to prevent the spread of animal diseases. Animals have to be shown to be disease-free and may have to be kept in isolation for a period on entering the country to make sure they are not carrying disease (quarantine), and they are tracked throughout their life in New Zealand.

There are specific standards for importation of all different fruits and vegetables from different parts of the world that may carry particular pests. Also, crops must not carry soil with them that may contain damaging pests and diseases.

Nature of science

Biosecurity is a good example of how evidence-based scientific conclusions can result in direct action.

There is increasing pressure on the systems in place to maintain biosecurity due to increasing levels of imports (up 76% in the last decade) and tourism (up 93% in the last decade). As well as increasing the number of staff who can perform checks on imports, technology has developed that allows scientists to detect the presence of pests in random samples taken from large quantities of imported produce.

Useful links

Visit the New Zealand government biosecurity website.

    Published 9 September 2008