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Ongoing project

Macadamia integrated disease management (MC16018)

Key research provider: The University of Queensland

What’s it all about?

Beginning in late 2017, this project is tasked with delivering a holistic integrated disease management program – which is compatible with integrated pest management – to increase the productivity and profitability of macadamia growers and the Australian macadamia industry at large.

Its work includes a combination of research, training and communication activities, to improve management approaches and diagnostic capabilities for a range of priority diseases for the industry, including husk spot, Phomopsis husk rot, flower bight complex, Phytophthora root rot, and branch dieback.

The researchers have continued their research, extension and diagnostic activities, specifically…


Field trials are being set up to investigate the effectiveness of eight fungicides against various pathogens causing diseases in macadamia, including husk spot, husk rot and flower blights.

Field trials are also underway to examine the effectiveness of cultural practices such as the influence of insect pest management on husk rot incidence.


The team contributed to over ten face-to-face industry meetings including MacGroups, crop consultant meetings, workshops and trainings, providing many opportunities for growers to learn about, and contribute to, project activities.

new guide to macadamia diseases was developed for these workshops, which growers can use to pinpoint problems in their orchards.

Diagnostic services

35 samples were received from growers, consultants and macadamia nurseries for identification with results and advice allowing growers to make decisions about management in their orchard.


Through the project team’s consultation with industry and other R&D initiatives, research activities within the project have now been planned and will include…

  • Building a better understanding of the biology and spread of priority diseases

  • Looking at disease resistance, including investigating varietal susceptibility and developing tests for screening germplasm for resistance traits

  • Diagnostic and surveillance work, including developing and assessing diagnostic protocols and working towards early detection and characterisation of new and emerging pathogens

  • Crop protection activities including screening and looking at the efficacy of crop protection products, developing use patterns for them and developing disease management strategies.

At the time of writing, work to assess the efficacy of select fungicide products was underway. In December 2017, two field trials were established in commercial macadamia orchards in Bundaberg to examine the effectiveness of three products on the incidence of Phomopsis husk rot, with effects on yield currently being assessed. Data collection on the effect of the treatments on yield are currently underway. Arrangements are also in place for further Phomopsis work, plus efficacy field trials for flower blight that will take place in the Northern Rivers, Sunshine Coast and Gympie.

Investigations on the factors and conditions that influence disease outbreaks are also underway. This information will underpin disease management strategies developed by the project. The project team report that recent research activities on Phomopsis husk rot have improved knowledge of the causal agent, including revealing that the disease is caused by two new species within the fungal pathogen Diaporthe genus, which are unique to macadamia. They add that there are significant variations in varietal susceptibility, which the researchers will explore with the industry’s breeding program (MC14000).

In working towards its goals, the project will also be developing the next generation of researchers for the industry. The University of Queensland has awarded scholarships for two PhD students to work on the project, with their work focused on flower blight (the pathogen biology, disease epidemiology and host-pathogen interaction) and the ecology and host-pathogen interaction of Phytophthora in macadamia.


The project has produced the below fact sheets for identifying diseases…


Related levy funds

This project is a strategic levy investment in the Hort Innovation Macadamia Fund