Forestry pest & disease management

Managing potential pests and diseases is an important part of caring for a forest. Find out what sorts of pests and diseases could affect your forest and what to do if you find any.


There are many pests in New Zealand that can affect our forests – from plants and flowers to insects and animals.

The New Zealand Farm Forestry Association (NZFFA) has a database of forest-specific pests known to be in New Zealand.

Common pests

Some pests are more common in New Zealand than others.


All trees are prone to some level of disease threat. Some diseases only affect certain species of tree or certain regions of forestry.

Kauri dieback

Kauri dieback is threatening New Zealand's kauri trees with extinction. MPI is working with central and local government, tangata whenua and the wider community to stop the spread of the disease.

Pine needle diseases

Pine needle diseases can cause large-scale damage to plantation forests and have significant economic impact.

Regional pest management plans

Many regional and district councils require landowners to manage and control certain pests and diseases – as per the National policy direction for pest management. Check with your council to find out what responsibilities you may have.

Beneficial organisms

Just as some organisms can be bad for your forest, others can be good. Beneficial organisms are creatures and plants that help control pests and diseases in your forest and boost the forest's overall health.

Insects can be used to control weeds

Some insects can be used to control invasive weeds. Landcare Research has a good guide to collecting and distributing insects as control agents for a range of weeds, including:

  • broom
  • gorse
  • hawkweeds
  • Japanese honeysuckle
  • lantana
  • mist flower
  • old man's beard
  • Tradescantia

MPI is also working with Scion to investigate the use of insects to control other insects. Import of a Tasmanian parasitic wasp, Eadya paropsidis, has been approved so Scion can research how effective it would be in controlling Eucalyptus tortoise beetles.

A list of Scion's current biocontrol projects can be found on its website.


In New Zealand, symbiotic fungi from the genus (a level of grouping plants or animals that's broader than species) Trichoderma are used to protect against pathogens (organisms that cause disease). A symbiotic fungus is a type of organism that produces spores and relies on its relationship with other organisms in its environment to survive.

When the fungus is applied to soil at the same time as seed, it colonises the outer shell of the seed and provides a protective layer that shields the seed from diseases in the soil.

The forestry industry has invested heavily in research into these fungi. If successfully managed and applied, they have the potential to protect against current threats and help trees protect themselves from unfamiliar diseases.

Monitoring pests and diseases

MPI keeps a register of pests and diseases known to affect primary industries.

Tell us if you see anything unusual

New Zealanders are expected to report unusual organisms to MPI. An unusual organism may be:

  • an animal pest
  • a plant pest
  • signs of plant or animal disease.

If you spot anything out of the ordinary in your forest, call 0800 80 99 66 and let us know.

Who to contact

If you have questions about the information on this page, email

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