Preparedness and management of huánglóngbìng (Citrus greening disease) to safeguard the future of citrus industry in Australia, China and Indonesia (Phase 1)

two lemons in a tree
Project code
AUD 569,301
Research program manager
Ms Irene Kernot
Project leader
Dr Jianhua Mo
Commissioned organisation
NSW Department of Primary Industries
JUN 2022
JUN 2024
Project status
Legally committed/Active
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This project aims to leverage global knowledge and investigate effective and efficient options to manage citrus Huanglongbing to increase the capacity of smallholder citrus growers in Indonesia and China to manage the citrus disease and, enhance the preparedness of the Australian citrus industry for future incursions of this disease.

Huanglongbing (HLB), or citrus greening, is a destructive disease of citrus (Bové 2006, 2014), associated with the phloem-limited Liberibacter bacteria. HLB is caused by ‘Candidatus Liberibacter asiaticus’ (CLas) and is spread mainly by the Asian citrus psyllid (ACP) (Diaphorina citri) and infected propagation material.

Indonesia produces around 1.5 million tonnes of citrus over approximately 70,000 ha (Supriyanto et al. 2017). Citrus is a fruit with high economic value in Indonesia (Ahmad et al. 2010). Between 1960 and 1970, three million HLB-infected citrus trees were destroyed in Indonesia (Beattie et al 2010). Production was reduced from 21 tonnes/ha to approximately 10 tonnes/ha, significantly denting the citrus industry in Indonesia (Supriyanto et al. 2017).

Australia produces around 700,000 tonnes of citrus over 28,000 hectares. The total production value in 2017/18 was approximately $829 million (Australian Horticulture Statistics Handbook: Fruit 2017/18) making citrus Australia’s second most valuable horticultural crop after almonds. HLB and its psyllid vectors are currently absent from Australia and are considered the biggest biosecurity threat to Australia’s citrus production. Preventing exotic pests and diseases from coming into Australia and developing preparedness for future incursions is a priority for the industry (Hort Innovation 2017).

In this project we will leverage international expertise to tackle the deficiencies in current HLB management practices by conducting a trilateral project with partners from Australia, Indonesia and China to enhance the sustainable management of HLB/ACP in Indonesia and increase the preparedness of the Australian citrus industry for an incursion of HLB/ACP.

Expected project outcomes

  • Understanding smallholder farmers’ current HLB/ACP management practices and attitudes towards HLB in their orchard
  • Determining the agronomic performance, disease tolerance and commercial applicability of HLB-tolerant rootstocks in Indonesia and Australia
  • Determining the agronomic performance of high-density plantings in Indonesia
  • Validating reported ACP repellents
  • Determining best intercropping models for HLB management in Indonesia
  • Determining best traps for ACP surveillance in Australia
  • Improving citrus growers’ understanding of HLB management principles and techniques in Indonesia and Australia.
map showing countries of south east asia
Key partners
NSW Department of Primary Industries