This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

A source of disease free, true to type genetic material had to be maintained by the Australian Citrus industry to protect it from the spread of both exotic and endemic graft transmitted disease, thereby protecting the industry from reduced productivity due to diseased orchards.

A key component of this was the maintenance of the insect proof repository, which provided the citrus industry (through the not for profit industry organisation Auscitrus) with high quality material to establish budwood source blocks. This resource was an industry asset, and was considered valueble given it was a key component of a holistic biosecurity plan for the Australian citrus industry.

This project successfully improved and maintained the existing virus free/pre-immunised repository system by moving just over half of the existing virus free foundation trees to a new insect proof repository at Dareton NSW. The maintenance of two insect proof repositories provided a level of redundancy if a catastrophic event such as fire, vandalism, or disease infection occurred at one of the sites.

A single tree of each variety had been retained at the virus free repository at EMAI Camden NSW, to provide a backup source of genetic material if it was required.

Additionally, pre-immunised trees of all grapefruit varieties were held at EMAI, which provided a source of grapefruit genetic material which had been immunised against the severe strains of grapefruit stem pitting tristeza virus.