Australian sweet persimmon industry development project – phase 4 (PR13007)
Status: Ongoing project
What’s it all about? Established in 2014 and due for completion in the coming months, this project is fourth in a line of projects with a focus on developing new technologies and management strategies for the industry. It has major objectives of investigating pre- and post-harvest management of mealybug and clearwing moth, clonal rootstock propagation, identifying lead and fruit diseases, and finalising post-harvest management protocols.
What’s the latest update? In regards to the rootstock research in this project:
- There has been ongoing monitoring of Fuyu and Jiro persimmon varieties, each grafted to nine different rootstocks, at Maroochy Research Facility on the Sunshine Coast.
- To date, there has been no demonstrable graft incompatibility for any of the rootstocks.
- There was, however, moderate overgrowth of the scion in the first growing season (the trial was planted back in winter 2015). The researchers continue to monitor this to determine what, if any, effect is had on tree growth or fruit production.
- In December 2016, most trees started a growth flush and initial tree training was due to take place this season. Tree vigour and framework are to be assessed as a result.
The rootstock trial at Maroochy Research Facility, photographed in December 2016
The project has also recently involved astringency removal work, with a carbon dioxide (CO2) deastringency technique trialled for the first time during the 2016 harvest season. In the trial, a small amount of fruit was placed in a purpose-built, small-scale gas chamber and exposed to a CO2 concentration of 95+ per cent for 24 hours. The approach proved successful. A taste panel assessing samples of the treated fruit, and non-astringent variety Fuyu, reported no significant difference in palatability ratings. This work was to be continued with treatment of astringent variety Rojo Brillante when sufficient fruit quantities became available.
Finally, the researchers have been compiling new information on chemical controls for mealybug, as well as recommendations on practices to extend the storage life of fruit. This information was to be included in revised post-harvest and integrated pest and disease management manuals for the industry, which will be distributed through industry and Hort Innovation channels in the near future.
In brief, on mealy bug:
- Systemic insecticides provide effective control of mealybug and have advantages over broad-spectrum and contact insecticides. Research suggests the most effective is clothianidin (Samurai), when applied as a soil drench.
- It is recommended the soil drench is used at flowering and in combination with foliar applications of either Transform or Movento before harvest, the latter where required by late-season mealybug numbers.
Findings on storage life suggest an ability to extend the season of fruit supply to the domestic market, and to confidently export. This is a result of post-harvest studies demonstrating the potential to lengthen the storage interval of persimmons, from the current industry practice of two weeks to at least eight weeks, using 1-MCP (Smartfresh) either with or without a modified atmosphere bag.
Persimmon industry extension and communication program (PR16001)
Status: New project
What’s it all about? Beginning in January this year, this project will drive the awareness and adoption of R&D outcomes within the Australian persimmon industry. Its strong communication and extension initiatives are designed to keep growers and other industry stakeholders up-to-date with the latest research activity, marketing initiatives and other news and issues. They will include the bi-annual Persimmon Press e-newlsetter, facilitation of industry field days and conferences, and management of the Persimmons Australia website.
What’s the latest update? As this project is only just beginning, a more detailed update will be provided in future editions of Hortlink. Run under this project, the 2017 Australian Persimmon Industry Conference and Field Day is to be held across two days on June 14-15 2017. For more information, see the Hort Innovation event calendar here.