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Eucalypt health

The NZDFI's eucalypt health research focuses in insect pests. While there is no avoiding eucalypt pests, researchers are working on the premis that negative impacts on eucalypt productivity can be minimised. The key is in identifying sustainable techniques for managing pests as an integral part of forest management.

Research programme and methods

Our research programme has two approaches:

1. Selection for pest tolerance

We are now well into research to identify differences between species and families in terms of tolerance to insect pests currently threatening NZ eucalypts. These include Paropsis charybdis and the recently arrived eucalyptus variegated beetle (EVB). The research has involved a significant screening programme within NZDFI's trial sites, quantitatively assessing pests and pest damage, and also parasite activity.  The aim is to:

  • identify and remove the most susceptible genotypes from unimproved material
  • retain and improve the least susceptible genotypes as part of future NZDFI genetic improvement work.

A summary of research in this area is available:

Eucalyptus resistance to paropsine beetles (Leslie Mann and Steve Pawson, SWP Technical Report 140, December 2021).


2. Improve monitoring and develop thresholds for management intervention

We need to be able to answer the question: "When is it worth managing pests?"

Our overall aim is to provide growers with tools and knowledge to manage pests only when economically necessary, so reducing the  cost and environmental impact of pesticide use.

Research on assessing the impacts of the severity, frequency and timing of defoliation, has been completed by Huimin Lin, and has produced some very valuable results.

Recent research updates and presentations

Check out our Resources, especially our six-monthly Project Updates, to read about how research is progressing.

Two recent workshop presentations are also available:

Managing insect pests in durable eucalypt plantations (2018)

Eucalypt health: defoliation, impacts and monitoring (2017)


Paropsisterna cloelia beetle laying eggs.

Late instar Oechalia schellenbergii nymph preying on a late instar Paropsisterna cloelia larva.




Paropsis beetle: a major defoliator of some eucalypt species.







Enoggera parasitising EVB eggs.






Severe gum emperor moth damage.


Gum emperor moth larva enjoying a feed.

Experiments to simulate defoliation.

Key researchers

Dr Steve Pawson leads the NZDFI eucalypt health team at the School of Forestry.

Leslie Mann and Carolin Weser are PhD students working on eucalypt health.

More information

Contact Dr Steve Pawson at the School of Forestry for more information.