Hort Innovation continues to invest the citrus R&D levy in a number of key projects for the industry, including work to strengthen and grow market access, develop new varieties and support the uptake of new information and practices by growers. Read more in the R&D snapshot below. To see how the industry’s marketing levy is being put to use, head to the marketing snapshot.


After you’ve read about the citrus industry’s current levy investments and outcomes in this edition of Hortlink, check out Hort Innovation’s citrus grower page. The grower page remains your one-stop-shop for industry information, including:

  • Important updates regarding the citrus Strategic Investment Plan (SIP), as available. Developed in close consultation with growers and other industry stakeholders, the SIP is a document outlining the priorities for strategic investment in the industry. It is to be used like a ‘roadmap’ by the citrus Strategic Investment Advisory Panel (SIAP) when providing advice to Hort Innovation on potential levy investments.
  • The latest updates regarding the citrus SIAP, including details on the panel’s recently appointed chair, Richard de Vos, and summaries from all SIAP meetings to date. The SIAP met at the beginning of February this year, and is due to meet again in early May.
  • The 2015/16 citrus industry annual report, detailing activities from the previous financial year.
  • Grower resources, events and articles of interest to the citrus industry.

Any questions?

As well as Hort Innovation’s citrus grower page, Hort Innovation Relationship Manager Brad Wells is always available to answer questions on the citrus program, on 0412 528 398 or at For questions relating specifically to the industry’s marketing, contact Hort Innovation Marketing Lead Graeme Yardy.



Increasing market access, profitability and sustainability through integrated approaches to fungal disease control (CT13020)

Status: Completed project

What was it all about? Established in 2013, this project addressed fungal disease control in the citrus industry with the goals of minimising the financial impact of fungal diseases, and overcoming market-access barriers related to them. It had a specific focus on citrus black spot (CBS) and emperor brown spot (EBS), and included the investigation of:

  • Fungal disease control protocols
  • Improved fungicide options
  • The use of disease-resistant varieties to reduce the use of fungicides.

During its life, the project:

  • Evaluated fungicides in the field for efficacy against CBS and EBS. There were 11 alternate fungicides screened over four seasons. Four promising fungicides were identified with registration potential for EBS (SDHI fungicides fluxapyroxad and boscalid, and multisite fungicides captan and dithianon), which were up to twice as effective as standard mancozeb. There was one promising fungicide identified for both CBS, also effective for EBS (multisite fungicide dithianon).Subsequently, efficacy and residue data was provided to support the application for a new minor use permit for captan, for the control of EBS in mandarins. Permit PER82043 was issued by the Australian Pesticides and Veterinary Medicines Authority in October 2016. The rate and use pattern of the permit were determined by this project, with the use pattern focussed on a major gap that occurs in the existing fungicide use patterns during autumn/winter, when EBS is typically most damaging.
  • Evaluated the duration of fungicide efficacy in the field. The researchers generated ‘efficacy decline curves’ for commercially used fungicides and promising new fungicides, showing rapid decline can occur within as little as 11 days after application, but can persist for up to 30 or so days. The researchers note that the potentially very short time frames for high-level protection in the field were surprising, as it is anecdotally accepted that four-to-six-week spray intervals may be sufficient. They recommend a need for a shift in fungicide application practices towards targeting forecast infection events, as opposed to calendar-based applications.
  • Conducted preliminary evaluations of fungicide reside profiles and post-harvest reside removal treatments. The reside profiles of any new fungicides – and the potential for post-harvest reside removal – need to be determined in order the maximise the likelihood of registration of new fungicides. Residue data supported favourable residue levels in fruit treated with promising new fungicides, and indicated up to five-fold reductions in fruit residues from standard packing line procedures.
  • Was involved in EBS resistance breeding, providing support to the industry’s breeding program to produce an additional 12,750 resistant mandarin hybrids during the project’s life. The researchers note that resistance to EBS is under simple genetic control and is readily achievable through hybridisation breeding followed by screening of hybrids for resistance.
  • Undertook laboratory screening to test the sensitivity of CBS to commercial post-harvest fungicides. The researchers note that a major step forward for overcoming trade barriers due to CBS would be the development of a post-harvest fungicide, but current commercial treatments do not offer reliable control. This research supported the idea that this poor post-harvest fungicide efficacy against CBS is actually due to poor fungus/fungicide contact, opening the door for further investigation and protocols.

Full details can be found in the project’s final report, which will soon be available to order at Final reports are free to Australian horticulture levy payers, registered Hort Innovation members and industry representative bodies.

Black spot symptoms

Symptoms of citrus black spot, including (a) hard spot, (b) freckle spot, (c) virulent spot, (d) speckled blotch, (e) virulent spot with pycnidia, and (f) pycnidia within a hard-spot lesion

 Evaluating new citrus varieties 2013-17 (CT12026)

Status: Ongoing project

What’s it all about? Established in 2013, this project continues the evaluation of new varieties of citrus. Among its goals are to boost grower productivity and profitability, diversify the Australian varietal mix, meet new and changing consumer demands, and provide new domestic and international market opportunities.

What’s the latest update? As part of the project, promising varieties are tested in a range of climates, soil types and on a range of rootstocks in different regions of Australia. Factors assessed include fruit quality, maturity periods, tree yield, fruit size, tree growth rate and specific management requirements.

New varieties are presented to industry through farm walks, field days, seminars and other extension activities, with varietal performance data available to growers to help select the variety, rootstock and environment in which to establish new citrus developments or re-develop existing plantings.

Some project updates:

  • During 2016, 15 new citrus varieties were added to the evaluation program, bringing the total to 33 new varieties since late 2014. Two of the varieties – the Nadorcott SL mandarin and Royal Honey Murcott mandarin – produced their first fruit in 2016, with evaluation begun for fruit quality and crop yield, and draft variety factsheet produced.
  • During 2017, field evaluation is to occur on 17 new varieties, and finished on 28 varieties.
  • There is the continued collection of data and updating of information sheets for a number of varieties in the program. During December, information sheets were drawn up for:

Dekopon mandarin
FJ navel orange
Brown skin navel orange
Kirkwood Red navel orange
Turkey Valencia orange
African Sunset mandarin
Summerina mandarin
Mandared mandarin
Hadass mandarin
Orri mandarin
Gold Nugget mandarin
Tarocco Ippolito blood orange
Eureka SL lemon
Tango mandarin

The information sheets will be made available to industry in the coming months, including via the Hort Innovation citrus grower page.

Citrus evaluation

A grapefruit variety being assessed for ‘trueness to type’ as part of project CT12026

Evaluation and commercialisation of new citrus rootstocks (CT13042)

Status: Ongoing project

What’s it all about? Running since 2014, the goal of this project is to make promising new rootstocks commercially available to the Australian citrus industry. Matched to local environmental and soil conditions, the rootstocks will help improve tree health, fruit quality and yield. The work will ultimately allow growers to intensify plantings, modernise orchards and obtain higher yields with minimal extra inputs.

What’s the latest update? Recent work in the project has included the continuation of short-term field trials to evaluate the potential of locally-bred and introduced rootstocks, including Vietnamese rootstocks grafted to Lane Late navel, Navelina navel, Eureka lemon and Imperial mandarin cultivars. Scion fruit yield, fruit size and fruit quality are all currently being assessed in this specific work. The short-term trials will provide early indications of any incompatibility issues with standard cultivars, and are also allowing rootstock validation under field conditions including disease.

In April this year, the researchers also plan to establish new trials to assess the dwarfing effect with Chinese and US rootstocks at the Dareton Agricultural Research and Advisory Station in New South Wales, with selected Chinese rootstocks also to be establish at multiple growers’ properties.

Meanwhile, a semi-commercial rootstock trial in the Riverina region is being conducted involving juicing Valencia oranges.

Rootstock trees ready for planting

Chinese rootstock trees ready to be planted in April this year as part of a grower-involved trial

Australian citrus industry innovation and market development program (CT15012)

Status: Ongoing project

What’s it all about? Beginning in 2016, this project supports a range of personnel to help develop a globally competitive and well-informed citrus industry that can reliably supply product that satisfies market requirements. These personnel include:

  • A market development manager (MDM), to help facilitate reliable supply, overcome market challenges and identify new opportunities. Activities of the MDM include the coordination of exporter groups, trade missions, crop forecasting and biosecurity work.
  • A market access manager (MAM), to help the industry overcome barriers to trade. Activities of the MAM include updating the industry’s export strategy plan and export manual, working with stakeholders to improve phytosanitary protocols, and advising on Free Trade Agreements.
  • A market information manager (MIM) to engage all value-chain participants to capture and disseminate timely information on supply, market conditions and shipping movements.

What’s the latest update? Project activities remain many and varied, with the three managers engaging with growers, packers, exporters, retailers, government and researchers in order to protect the citrus production base; prioritise market-access initiatives; streamline export registration procedures; provide market information; and improve product offerings for domestic and international markets.

As a sampling, recent key activities have included:

  • Continued delivery of monthly Season Updates for growers, which provide a summary for the major citrus growing regions including seasonal outlooks and advice of nutrition, irrigation, pest and diseases and more. Find the latest Season Update documents at
  • Provision of weekly reports on shipping volumes and conditions in export markets.
  • Provision of production data via InfoCitrus during the season – see more and log in to the InfoCitrus database here.
  • Delivery of training for registered crop monitors, with new online training material produced and delivered from November last year. The crop monitors are responsible for surveying orchards for pests and diseases as part of the process of exporting to Korea, China and Thailand.
  • Facilitation of the industry’s online export registration system. At the end of 2016 and into early 2017, the project assisted growers and packers in lodging export registration applications for the 2017 season, which included face-to-face visits in all major growing regions and support via phone and email.
  • Work towards the 2017 crop forecast, which is expected to be released to industry in March, and fruit density and sizing surveys to help inform the industry of the quantity and quality of fruit.
  • Facilitation of the national tree census, which was conducted online between November 2016 and the end of January this year. At the time of writing, data was still being analysed.
  • Participation in and facilitation of export, variety, agrichemical and domestic/quality leadership groups, as well as Japan, China and US exporter groups.
  • Participation in relevant trade events including the China Fruit and Vegetable Fair held in Beijing in November 2016, which was an opportunity to showcase Australian citrus and strengthen relationships and communication with relevant authorities. In 2016, the project team also visited the Philippines to present the Australian citrus supply chain to retailers, and visited Japan to meet with retailers and importers.
Citrus industry communications (CT15009)

Status: Ongoing project

What’s it all about? This project delivers effective and timely communications to ensure Australian citrus growers and other industry stakeholders are kept up-to-date with the latest R&D and marketing activities, and other industry news and information. Among its key goals are to support decision-making within citrus businesses and to facilitate the uptake of new research and technologies, to ultimately strengthen the profitability and sustainability of the industry.

Its work is supported by the project Citrus Australia Limited – communication support on CT15009 (CT15015).

What’s the latest update? A number of regular communication channels continue to be produced and maintained by this project, including but not limited to:

  • The quarterly national magazine, Australian Citrus News, which has been redesigned under this project
  • Monthly Season Update newsletters, also recently redesigned
  • Fortnightly Citrus eNews e-newsletters
  • The industry website,

The project also produces industry media releases as required, maintains a photography database, and develops grower case studies for peer-to-peer learning.

Development of national strategies to manage citrus gall wasp (CT15006)

Status: Ongoing project

What’s it all about? Citrus gall wasp is a major and widespread pest in citrus. Established in 2015, this project is developing national management strategies for the wasp based on:

  • Enhanced biological control
  • Better timing of control actions, through investigation of the relationship between weather and the wasp’s development (the development of ‘degree-day’/phenology models)
  • Improved use of oil and other potential repellents
  • Identification of new insecticide options compatible with integrated pest management approaches.

What’s the latest update? No new milestone report was due in the period since the last edition of Hortlink (Spring 2016), but you can read more about the project in our profile of its lead researcher at the bottom of this page.

At the time of last reporting in Hortlink, the project’s activity had focused on the efficacy of petroleum spray oil in deterring citrus gall wasps from laying eggs. This work used BioPest® paraffinic mineral oil and lemon shoots as the host material. It found that at a one per cent rate, the oil was successful in preventing egg-lay in all test shoots, but that at an 0.5 per cent rate the oil was not be sufficient in the control of citrus gall wasp (a finding supported by anecdotal evidence from some growers).

At the time of last reporting, other work had included:

  • Field trials to confirm the effectiveness of Surround® in deterring egg-lay, and to confirm the effectiveness of Samurai and Confidor Guard in controlling citrus gall wasp larvae
  • Estimating the effect of heat stress on the survival of citrus gall wasp parasitoids
  • Ongoing collection of citrus gall wasp phenology data.

This year, activities in the project were to include:

  • Investigating the scope for reducing Surround rate
  • Mass rearing of citrus gall wasp parasitoids
  • Collection of toxicity data of Samurai on key beneficial insects in citrus
  • Autumn application of Samurai and Confidor Guard in Valencia blocks
  • Effects of hedging timing on citrus gall wasp control and yield
  • Development of a citrus gall wasp infestation map
  • Scoping studies of factors affecting the selection of egg-lay sites and orientation by citrus gall wasp
  • Releases of parasitoid wasps.
Development of phenology models and a timing guide for the management of Californian red scale in Australian citrus (CT15008)

Status: Ongoing project

What’s it all about? Aphytis wasps and petroleum spray oils are used in the control of Californian red scale (CRS) in Australian citrus crops – but they are only (or mostly) effective at certain life stages of the pest, and thus timing is everything.

This project is developing degree-day-based phenology models to predict the timing of peak abundance of vulnerable life stages of CRS to better guide Aphytis releases and oil applications.

What’s the latest update? No new milestone report was due in the period since the last edition of Hortlink (Spring 2016). At the time of last reporting, the project was still in the early stages of data collection. During the 2015/16 season, seasonal patterns of CRS male flights had been monitored, with pheromone traps placed at three sites in the Riverina area and two sites in Sunraysia.

This first-year data showed multiple peaks of male flight over a season. The first two post-winter peaks occurred around similar dates across the different sites.

The researchers noted that, together with crawler data, timing of the two male flight peaks could be used to predict when crawlers are likely to become abundant, and hence when to spray to achieve a better control of CRS populations.

Australian Citrus Quality Standards – stage 3 (CT15013)

Status: Ongoing project

What’s it all about? Established in 2011 and now in its third stage, the Australian Citrus Quality Standards program has an overarching goal of ensuring the price of Australian citrus is maximised. To do this, it is working to solidifying the industry’s reputation as a reliable supplier of high-quality citrus, capitalising on aspects of taste, colour, freshness and food safety.

Some of the key objectives of the project include:

  • Capturing and disseminating maturity levels of fruit for sale in the wholesale market to inform marketing decisions
  • Developing and implementing procedures to improve quality outcomes, including a maximum granulation standard for Imperial mandarins to help restore consumer confidence
  • Increasing knowledge in the supply chain to achieve greater adoption of quality improvement practices
  • Developing a standard operating procedure for start of harvest that reduces the likelihood of immature fruit entering the supply chain.

What’s the latest update? No new milestone report relating to the project was submitted in the period since the last edition of Hortlink (Spring 2016). At the time of last reporting, project activities had included:

  • In-market citrus quality testing, with reporting including an Imperial mandarin granulation assessment for the first time. Australian Citrus Quality Standards reports were being provided to value-chain participants as a result.
  • A maximum granulation standard had been developed and endorsed by the Citrus Australia board. At the time of last reporting, the standard was being extended to the citrus industry through Australian Citrus News and presentations at meetings. Quality standards materials were also being developed for quality-control personnel across the value chain.
  • A citrus maturity calculator app for iPhone and Android devices continued to be updated and maintained.
  • The Manager of Citrus Quality and Information (MCQI) continued to liaise with the entire supply chain on Australian Citrus Quality Standards, including visiting packing sheds, participating in regular teleconferences with packers, and meeting with quality assurance teams at the large retailers.
  • A pilot standard operating procedure for harvest protocol had been raised with retailers and a draft was being prepared – it was intended that the procedure be in place for the 2017 picking season and anticipated that it be extended to growers shortly.
  • A pilot program of pre-season testing and reporting had been conducted early in 2016, with learnings to be applied for the 2017 season and results to be extended to industry.
  • Citrus Quality Community of Practice and Domestic Market Leadership Groups had been established.
Other R&D projects of note…
  • MRL risk analyses and risk management options for major citrus export markets (CT14003), which collects, prepares and supplies maximum residue limit (MRL) information to keep the Australian citrus industry informed of changes that could lead to pesticide-related market problems for exporters.
  • Agrichemical residue monitoring program for Australian citrus exports – stage 2 (CT15016). Beginning in 2016, this project works to ensure exporters have effective residue risk-management strategies in place and continues, improves and expands on the Australian Citrus Pesticide Residue Monitoring Program (ACPRMP). The ACPRMP involves the testing of Australian citrus for a range of chemical residues and potential contaminants, to ensure the industry can meet quality assurance and certification requirements for domestic and international markets.
  • Australian Citrus Post-Harvest Science Program (CT15010), which began in January this year to continue the industry’s post-harvest science and technology program. The program is responsible for delivering new information and innovative technologies to improve the quality of Australian citrus, with ultra-low chemical residues. Further updates will be provided as this new iteration of the program gets underway.
  • Citrus technical forums (CT16700), which is responsible for the planning and delivery of the biennial Citrus Technical Forums. The 2017 event is to be held in early March this year, with details available here and in Hort Innovation’s new calendar.
  • Protecting Australian citrus germplasm through improved diagnostic tools project (CT14009). Running since 2014, this project is assessing, developing and validating diagnostic methods for a number of endemic graft-transmissible pathogens of citrus to help secure the high health status of the Australian citrus industry. The project also aims to boost Australia’s preparedness for an incursion of devastating citrus disease Huanglongbing. It has recently drafted two fact sheets for industry on citrus viruses and viroids, which are soon to be released.
  • Protecting Australia’s citrus genetic material (CT15005), which continues to fund the long-term National Citrus Repository (NCR) program for publicly owned citrus varieties. It supports the maintenance and disease testing of foundation trees in the NCR and the disease testing of new Australian citrus selections entering the repository system. The NCR is an important part of an integrated biosecurity system designed to protect the health and economic viability of the Australian citrus industry. There are currently 117 publicly owned citrus clones housed by the NCR.
  • Building a genetic foundation for Australia’s citrus future through targeted breeding (CT15017), a new integrated breeding program that began in October 2016.



The early stages of 2017 have seen the continued development of a dedicated marketing and promotion program for citrus in Japan – a key market identified with industry.

Planned for May, the program will be implemented with the assistance of Austrade and involves three key elements:

  • Engaging Japanese consumers and trade customers online
  • Conducting a trade seminar for key contacts
  • Supporting retailers with in-store promotions on Australian citrus at peak season.

The online component of the program aims to raise the profile and in-market awareness of Australian citrus with Japanese consumers and trade customers. Also critical will be building an online presence where the latest information about the industry and the key benefits of Australian citrus are available at any time. Austrade will help facilitate feedback from the Japanese trade on the types of information to be shared and advise on suitable content for a Japanese audience. It is expected that this online presence will launch in line with other trade events in May this year.

The trade seminar planned for Tokyo and Osaka in May/June is designed to provide a season update to key Japanese trade contacts and strengthen the networks commitment to buying Australian citrus. The seminar will deliver targeted messages highlighting supply capabilities and production forecasts for the upcoming export season. It will position Australian citrus as a premium product by demonstrating unique selling features and points of differentiation. This will be a key event to enable the industry to continue to develop and maintain a strong network of key Japanese industry contacts.

The third pillar of the program will be the deployment of funding to support specific retailer promotion of Australian citrus through opportunities such as in-store sampling and demonstrations, and catalogue support. This activity will enable Japanese retailers to promote Australian citrus messaging and utilise premium positioning.

A more detailed update on the program will be provided in the next issue of Hortlink.



As citrus gall wasps impact crops in key growing regions across the country, NSW Department of Primary Industries (NSW DPI) entomologist Dr Jianhua Mo is working with industry to deliver a sustainable solution.

They are around 3mm in size, black and can live less than a week during spring. Despite their short lifespan, the citrus gall wasp can do significant damage to trees. Females lay up to 100 eggs under new bark growth, and once the larvae hatch, they can feed inside stems for 10 months before adults emerge. The end result can be swollen bulbs or ‘galls’ on tree limbs, which can impact tree health and cripple production.

However, the citrus gall wasp may have met its match through a project Hort Innovation is co-investing in with the NSW DPI, using citrus levy funds and contributions from the Australian Government. Headed up by Dr Mo, the project team has made a landmark discovery.

“One of the exciting parts of this project is that we have found the two main native parasitic wasp species – Megastigmus brevivalvus and M. trisulcus – in the new incursions areas in the south. With the continued effort to release the parasitic wasps and good integrated pest management practices, populations of the parasitic wasps are expected to rise up gradually and eventually bring down gall wasp numbers,” Dr Mo said.

The finding, combined with other management strategies being developed as part of this project, mean the pest’s days are numbered.

How parasitic wasps work

It’s been said nature has a way of sorting itself out and researchers have found this is very much the case in Queensland. In its traditional habitats in the north, citrus gall wasp populations are, in most years, kept below damaging levels by the two parasitic wasp species. Their attack is simple. The parasitic wasps insert their eggs into citrus gall wasp eggs, and after they hatch, the larvae feed on the citrus gall wasp larvae, eventually killing them.

Bringing solutions south

The citrus gall wasp is a relatively new pest in the southern Australian growing regions. It was first detected in the Sunraysia in the early 2000s and has since spread to all corners of Australia’s citrus growing regions.

Dr Mo said that managing the citrus gall wasp in southern Australia has been no easy task, with less prevalence of the parasitic wasps and limited chemical control options.

“The most challenging aspect of this project has been to quickly find management strategies for a pest that is rapidly expanding in distribution and is only visible for a few weeks in a whole year,” he said.

Parasitic wasp releases are taking place each year in new gall wasp incursion areas in the southern Australian citrus growing regions where the parasitic wasps have not yet established.

Chemical control findings to date

The team is in the process of trialling new chemical options on farms in the Sunraysia and Riverland. Findings to date have been positive. For example, Surround – a clay based product – has been found to be highly repellent to the adult citrus gall wasps, thereby reducing egg lay and gall numbers. On the other hand, several systemic insecticides have shown excellent control of gall wasp larvae inside the galls, resulting in reduced adult wasps coming out of the galls the following season.

Pruning as a control method

Dr Mo’s team are also investigating optimal gall pruning times to limit damage to trees and production, which Dr Mo said presents a unique set of challenges.

“If pruning is done sometime before the wasp emerges, removed galls will wither and wasps inside won’t emerge. However, if pruning is done too close to wasp emergence, the pruned galls have to be mulched or burned to prevent the wasps from coming out,” Dr Mo said.

“On the other hand, pruning also encourages new flush, making the trees more attractive to the pest. And pruning too late may reduce yield – so it’s vital we find that perfect balance.”

Where to from here

On top of a series of field days and workshops hosted by the researchers, Dr Mo and his team will continue to seek grower input throughout the life of the project, which will be complete in 2018.

The team is exploring the prospect of mass rearing of parasitic wasps using potted trees, mapping hotspots of parasitic wasps in key growing regions, investigating side effects of insecticides on beneficial insects in citrus, and developing integrated pest management strategies for the gall wasp.

The team will share its findings and recommendations with industry through future field days, industry representative body publications and Hort Innovation channels.

Read more about the citrus gall wasp project in this fact sheet from NSW DPI.

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