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Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.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 Risk Analysis workshop conducted by Auscitrus around the time of this project first starting showed the Australian Citrus Budwood Scheme was at significant risk from an incursion of HuanglongBing (HLB) and/or its insect vector, the Asiatic Citrus Psyllid (ACP).

All budwood production at the time was in open conditions, as the industry did not have significant insect vectored pathogens in their budwood production regions. This however would mean an incursion of ACP could infect the budwood source trees with HLB, which would restrict the supply of disease tested budwood to Australian citrus nurseries. In the event of an incursion the industry would be heavily reliant on a supply of disease tested budwood to combat the disease, therefore the protection of the budwood source trees was of utmost importance.

It was decided at this workshop that Auscitrus should implement an insect screening program for its budwood blocks as a matter of highest priority. Due to the size of our industry and the capacity of the budwood scheme to supply all Australia’s budwood needs, it was decided that the new budwood production system should be modelled on the long running and successful South African budwood scheme. All budwood should be produced under insect screened conditions in a rapid multiplication system, with the goal to produce sufficient volumes to supply 100 per cent of Australia’s citrus budwood requirements.

The most significant aspect of this strategy moving forward will be the construction of substantial insect screened structures, followed by the refinement of management techniques to produce budwood under screened conditions.

The production of budwood under screen poses significant challenges, and was a departure from existing Australian budwood practices. The South African budwood scheme closely mirrored the expected operating conditions of the future Australian budwood scheme, and they had been operating in this way for many years.

This study tour allowed the Auscitrus Manager and a member of the Auscitrus Executive Committee to visit the South African facility and discuss all structural and operational issues associated with running their scheme. A number of issues were identified that would affect the construction and operation of a future screened facility in Australia.

The timing of the tour coincided with an invitation to attend the South African Citrus Research International research symposium, adding value to the trip.