Citrus repository a comforting insurance policy for growers

Peace of mind cannot be measured in terms of dollar value, but Australia’s citrus growers certainly understand its true worth.

A resource supported through their research and development levy has provided growers, industry and Australian communities and consumers with an assurance of continued citrus production should adversity strike.

Through past and ongoing Hort Innovation investments on behalf of growers and the Australian Government, the National Citrus Repository Program has been established as an ‘insurance policy’ to protect our citrus industry against destructive, incurable diseases.

Managed by Auscitrus on behalf of Hort Innovation’s ‘Protecting Australia’s citrus genetic material’ investment and in partnership with New South Wales Department of Primary Industries, the repository houses more than 120 publicly-owned true-to-type “foundation tree” variety clones so growers can access clean, disease-free planting material for assured quality and yield protection.

Graft-transmissible diseases, spread by insects and/or infected plant material, are of considerable concern to industry as they can kill trees and decimate entire orchards – and there is no cure.

According to Hort Innovation’s Australian Horticulture Statistics Handbook 2022-23, the nation’s citrus production of 815,750 tonnes was valued at $977.1 million for that year. Almost 30 per cent of production was exported fresh, valued at $441.1 million.

Hort Innovation research and development manager, Ben Callaghan, says that given the value and importance of our citrus industry, shielding it from potential disaster is imperative.

“If we didn’t have the repository and we experienced an outbreak of an exotic disease such as huanglongbing (HLB) or citrus variegated chlorosis (CVC), the impact would be enormous in terms of cost to growers and industry, access to markets and the effect on consumers and regional communities,” Dr Callaghan said.

“It is difficult to put a true cost on the availability of clean, true-to-type planting material in these situations, as colleagues in overseas citrus industries will attest to.

“By providing growers with immediate access to clean planting material that is certified disease-free through this biosecure repository we can create a buffer against such potentially devastating repercussions by providing access to clean, true-to-type planting material for the Australian citrus industry when needed.”

Biosecurity is a strong focus for the nation’s citrus industry which has witnessed the devastating impact of HLB in other countries.

“This repository is an invaluable resource – it is a working insurance policy for industry,” Dr Callaghan said.

An impact assessment of the previous iteration of the ‘Protecting Australia’s citrus genetic material’ investment from 2018-2021 reported an estimated benefit-cost ratio of 6.17 to 1. Multiple positive impacts from the project included:

• Reduced risk of productivity losses and cost of replanting from the introduction and spread of graft transmissible diseases
• Reduced risk of higher chemical usage to manage insect vectors associated with some graft transmissible diseases
• Continued supply of affordable citrus for consumption, and community spillover benefits (ie employment) from a profitable citrus industry.

At the conclusion of the 2018-21 investment, 70 to 80 per cent of citrus plantings were using clean and true-to-type material sources from the repository program, through which a minimum of one tree of each citrus variety is held in insect-screened green houses at Dareton and Menangle in New South Wales.

Having repository houses situated in two different regions provides security of material should a catastrophic event such as fire, vandalism or disease incursion occur at one of the sites.

Through the current Hort Innovation investment, the National Citrus Repository Program is maintaining high health status foundation trees as a source of budwood for industry.

Budwood from the foundation trees is used by Auscitrus (an industry non-profit organisation) to create daughter trees and multiply large supplies of buds for industry.

New varieties can enter the program after pathogen testing and elimination if no known diseases are detected.

Through the previous investment, two new varieties were added to the repository based on commercial potential assessed by Auscitrus or community/industry interest. They were an imported mandarin variety (Shiranui) added in 2020 following propagation and processing at the Australian Post Entry Quarantine Facility managed by the Federal Government and a local pomelo variety (K15) added in 2019 following propagation and processing by the Citrus Pathology Team at the NSW DPI’s Elizabeth Macarthur Agricultural Institute at Menangle.

‘Protecting Australia’s citrus genetic material’ investment is collaborative project, linking into various citrus breeding, diagnostic and biosecurity programs being supported through Hort Innovation on behalf of industry.

Growers can purchase varieties from the repository through https://www.auscitrus.com.au/cfr-list/.