Project Leader, Organisation

Andrew Geering, University of Queensland




Many ornamental and Asian vegetable plant species host plant pathogens that are threats to agricultural and native ecosystems in Australia.  Trade of these plants is difficult to regulate, as they can be bought using electronic markets (eBay) or even at school fetes, and illegal importations by collectors or first generation Australians are commonplace. Several prominent plant viruses/viroids infect ornamentals, such as cotton leaf curl Multan virus in Hibiscus rosa-sinensis, and various pospiviroids and tospoviruses in a diverse range of plants. Knowledge of the risk posed by these ornamental and minor culinary species lags well behind that of important crop species.

Objectives and impact

The aims of this project are to:

1) Critically analyze the scientific literature and produce a host-pathogen index of plant virus and viroid records in ornamental plants in Australia.

2) Examine plant disease herbaria databases from Australia and retrieve specimens of unidentified viruses in ornamental and Asian vegetable plants for further characterization.

3) Undertake surveys of ornamental and Asian vegetable plants in Brisbane and Sydney urban and periurban areas to obtain specimens of plants with virus or viroid-like symptoms. Emphasis will be placed on species in economically important plant families including the Solanaceae, Malvaceae, Rosaceae and Poaceae.

4) Utilize high throughput sequencing technologies and bioinformatics pipelines to identify the viruses and viroids infecting the plant specimens. 

This project addresses the Foundation’s vision to enhance urban and peri-urban biosecurity. Ornamentals and Asian vegetable plants have barely received any attention as carriers of economically important plant viruses and viroids yet they represent important pathways for the introduction and movement of these pathogens. This project represents the first serious attempt to catalogue these threats.


This project has helped address the biosecurity threat posed by the trade of ornamental plant species. There are many well-documented examples of economically important plant pathogens crossing international borders in shipments of nursery plants or cut flowers, and this movement pathway is one of the most difficult to close due to the size and diversity of the industry. Fundamental to the operation of any biosecurity system is to have an accurate host-pathogen registry and one of the main tasks achieved in this project was to review the virus and viroid records from ornamental, turf and native plant species in Australia. Research was also done to investigate the diversity of viruses infecting common ornamental shrubs and turf grasses in Brisbane, Sydney and Darwin, using high throughput sequencing technologies. A remarkable diversity of viruses was detected, most of which were either new records for Australia or completely new to science. Two of the most significant discoveries were the widespread occurrence of bermuda grass latent virus in green couch grass and cotton bunchy top virus in ornamental hibiscus plants. This project has highlighted the need to pay more attention to ornamental plants as potential reservoirs of infection for viruses of food and fibre crops.

A copy of the Final Report can be downloaded here. Please Note: the appendices are not included in the report as the Authors are publishing the results. Please contact the Foundation or the Author (Andrew Geering) for more detail.