Project objectives:

To define the sugarcane pest and disease status of the eastern Indonesian islands, Irian Jaya, PNG, and the northern Australian islands and coastline.
To develop a resistance screening test for the shoot borer, Sesamia grisescens.
To refine a resistance screening test for sugarcane smut (caused by U. scitaminea)
To develop a sensitive assay for the disease Ramu stunt for use in germplasm exchange
To train staff in Australia, Indonesia and Papua New Guinea in quarantine of sugarcane.
Determine the presence of viruses and phytoplasmas within the region.

Purpose and context of project:

The project aims to conserve the Saccharum officinarum germplasm, which has a centre of diversity in Papua New Guinea and Irian Jaya. This germplasm is used as a sweetener by indigenous peoples of the area and is a valuable breeding resource for sugarcane cropping industries around the world. Surveys are a central aspect of the project and aim to determine the potential threats to this germplasm as well as the threats to cropping industries in each of the participating countries. Updated pest and disease listings for each country will be used to help construct quarantine and pest and disease control strategies aiming to minimise the risks to germplasm and industries posed by the spread of major pests and diseases. Training of quarantine and industry staff will help ensure threats are dealt with in due manner and the effects of pests and diseases minimised.

Collaborating Institutions:

Papua New Guinea: Ramu Sugar Ltd

Indonesia: Indonesian Sugar Research Institute

Australia: Bureau of Sugar Experiment Stations
Australian Quarantine and Inspection Service

Results

Updated pest and disease listings for each country: important for targeting quarantine strategies and developing appropriate controls. The first of four surveys was conducted in PNG in May-June 2001. Locations visited included Daru Island, Morehead, Tabubil, Vanimo, Wewak, Manus Island, New Ireland, New Britain, Lae, Popondetta, Alotau and Port Moresby. This highlighted the distribution of major pests and diseases within the country. Further information will be available when viral assays have been completed on collected leaf material. Visual diagnoses so far suggest Ramu stunt, Fiji disease, orange rust and chlorotic streak diseases are widespread while downy mildew was found only on the northern side of the island. Sesamia grisescens, the most important PNG stalk borer, was of more limited distribution. Evidence of previous collections on New Britain was found at National Agricultural Research Institute (NARI) facilities. Planthopper species of Eumetopina and Perkinsiella (some of which are able to transmit Ramu stunt and Fiji diseases respectively) were also widespread and were collected for further identification. It is proposed to undertake some specific smaller surveys, particularly from the Highlands (Mt Hagen) down to the Ramu Valley, and also a survey around the Ramu Sugar estate further down the Ramu Valley. The latter to assess the extent of spread of introduced exotic diseases from the estate. Further surveys of eastern Indonesia, northern Australia and the Torres Strait are planned for 2002-2003.

Sensitive assay for Ramu stunt: important for quarantine purposes in germplasm exchange between countries / regions. A research scientist was employed during the period and systems put in place to begin the research into the causal agent. A phytoplasma was reported to be associated with the disease by another research group but this needs confirmation.

Resistance screening test for Sesamia grisescens: needed at Ramu Sugar to improve the viability of their cropping industry. A resistance screening trial has been planted at Rau during the period with emphasis on looking at differences in a range of varieties known to display differences in tolerance or resistance to the pest. Half of the plots will be sprayed with insecticide to control the pest and half will remain untreated. A number of plant injury and insect parameters will be measured and these compared to differences in yield between sprayed and unsprayed plots.

Extension of the need for quarantine: Following the PNG, the need was recognised for the production of materials to publicise the need for sugarcane quarantine in PNG. Posters are being designed and will be produced for distribution within PNG.

Development of smut resistance screening test: critical to industries in Australia and Indonesia for preventing very large industry losses. Research has been initiated into methods to improve spore storage for use in resistance screening trials. Results should be to hand in the next 6-12 months. Australian canes are being screened at Pasuruan; many clones have been given resistance ratings and this information is being used in the Australian breeding program.

Facilities / infrastructure: A weighing tipper bin has been manufactured and shipped to Ramu Sugar for use in the harvest of project trials. The bin will make trial harvests much faster and facilitate the undertaking of more trials. A laboratory for the assay of ratoon stunting disease (RSD) has been installed at the Indonesian Sugar Research Institute in Pasuruan, Indonesia. This will assist with the control of this important disease in that country.

Results

Updated pest and disease listings for each country: important for targeting quarantine strategies and developing appropriate controls. Surveys have been undertaken in PNG, northern Australia and Indonesia. These have highlighted the distribution of important pests and diseases. Ramu stunt, a major PNG disease, is thought to be much more widespread in PNG than previously thought and may be significantly closer to the Australian industry than recognised previously. A survey of the Torres Strait, planned for early in 2003, should shed some light on this. No smut or ratoon stunting diseases was found on the PNG survey, a very positive result for the conservation of basic Saccharum germplasm in PNG. A number of insect pests were seen on the PNG survey; these include plant hopper species which transmit viral or phytoplasma diseases. Some of these were unrecognised and have been sent to relevant experts for identification. The distribution of stalk borers present at Ramu Sugar was also updated and will be used as a guide in the development of quarantine strategies.

Very few pests or diseases were seen across northern Australia in May-June 2002 and the region generally poses a low risk for pest and disease entry. However, centres such as Darwin where a diversity of ethnic backgrounds and cultures exists, pose a risk because sugarcane is cultivated in backyards with some clones potentially sourced from high-risk areas. The presence of sugarcane smut in Kununurra will continually pose a risk for the rest of the Australian industry.

A number of pests and diseases were seen during the Indonesian survey also conducted in May-June 2002. Leaf scald, sugarcane mosaic, several planthoppers and some other pests were seen in islands just to the north of Australia and could pose a threat both to sugarcane along the Indonesian Archipelago and also the Australian sugar industry. In all the surveys conducted so far, some results for unknown viral and phytoplasma diseases and for insect identifications are still pending.

Sensitive assay for Ramu stunt: important for quarantine purposes in germplasm exchange between countries / regions. Attempts to identify the causal agent have so far been unsuccessful. A phytoplasma has been reported to be associated by another research group but this cannot yet be confirmed. Research is continuing.

Resistance screening test for Sesamia grisescens: needed at Ramu Sugar to improve the viability of their cropping industry. Research has proved fruitful in identifying resistance to the borer and in progressing the development of a resistance-screening test. Plant parameters that may be measured to determine the resistance of canes to the pest are being identified. Lack of borer infestation in the most recent trials has hindered progress in the current year.

Training of quarantine staff: very important for preventing pest and disease spread between each country - hence the conservation of germplasm. Scientists from Ramu Sugar and Indonesia (Indonesian Sugar Research Institute) have spent time at BSES offices in Tully, Brisbane and Woodford learning more about Australian diseases and methods for disease assay (including molecular tests). A workshop for PNG quarantine staff at Ramu Sugar is planned and will provide an update of project activities.

Development of smut resistance screening test: critical to industries in Australia and Indonesia for preventing very large industry losses. Research has concentrated on storage of smut spores for resistance screening trials. Results have been good resulting in less time taken for spore collection and a more efficient testing procedure.

Updated pest and disease listings for each country This is important for targeting quarantine strategies and developing appropriate controls. Surveys have been undertaken in PNG (2001), northern Australia (2002), Indonesia (2002) and Cape York and the Torres Strait (2003). These have provided an important understanding of the distribution of major pests and diseases in the region. No other coordinated sugarcane survey of the region has ever occurred. The surveys highlighted the following:\

Ramu stunt, a major PNG disease, was found to be much more widespread in PNG than previously thought; No smut or ratoon stunting diseases was found on the PNG survey, across northern Australia (except for smut at the known infestation on the Ord River) or on Cape York or the Torres Strait.

The Indonesian survey highlighted that movement of sugarcane smut had occurred eastward from Java, closer to PNG and the eastern Australian industry. This had occurred with the spread of hybrid (commercial cultivar) material. Quarantine procedures in the region need to be improved.

The disease leaf scald has also spread east from Java in the same material. The widespread movement of hybrid sugarcane within the region was obvious. In PNG, villagers in even remote outer islands were growing sugarcane obtained from commercial crops at Ramu Sugar. This not only means that some chewing canes (S. officinarum) had been displaced, but that the potential for spread of several major diseases from the commercial cropping estate to disease-free areas was now significant.

The Cape York survey highlighted the lack of significant quantities of sugarcane between the cropping areas around Mossman and the garden canes in the Torres Strait Islands.

The finding of the planthopper Eumetopina at Bamaga (tip of Cape York) in just a couple of gardens, coupled with its isolated occurrence in the Torres Strait, suggests that eradication from the mainland of Australia is a real possibility.

The need for further quarantine training/materials. Two training workshops were held for Torres Strait and PNG staff but there remains a need for more training in both of these locations. There is a definite need in Indonesia. The spread of sugarcane from Java to the eastern islands of the Archipelago and to Papua is a grave concern and more work is needed in this whole region.

Sensitive assay for Ramu stunt

This is important for quarantine purposes in germplasm exchange between countries/regions. Attempts to identify the causal agent have so far been unsuccessful. A phytoplasma has been reported associated with the disease by another research group but this cannot yet be confirmed. Research so far has identified some unique tiny nucleic acids.

Resistance screening test for Sesamia grisescens

Screening is needed at Ramu Sugar to improve the viability of its cropping industry. Research has proved fruitful in identifying resistance to the borer and in advancing the development of a resistance-screening test. Plant parameters that may be measured to determine the resistance of canes are being identified. Lack of borer infestation in the most recent trials has hindered progress.

Training of quarantine staff

There were two important training sessions: in November 2002, AQIS officers from all parts of the Torres Strait were trained in pests and diseases of sugarcane in a workshop on Thursday Island; later that month PNG quarantine staff attended a three-day training workshop at Ramu Sugar. Here they saw major pests and diseases in the field and were exposed to important aspects of the project work. They left with a much clearer understanding of the significance of Saccharum germplasm in PNG, the need for good quarantine protocols, the importance of their role in quarantine and the nature of the pests and diseases of sugarcane within the region.

Pest and Disease Manuals Accompanying each training workshop was the distribution of the first sugarcane pest and disease manuals for both the Torres Strait and PNG. These will provide an ongoing source of information for quarantine officers.

On-going smut resistance screening

Screening is critical to industries in Australia and Indonesia, to help prevent large industry losses. Research has concentrated on storage of smut spores for resistance screening trials. The resistance screening has been ongoing, with over 900 clones now screened. Results have been good, and are being used to help the Australian industry prepare for a disease incursion. T

he Indonesian Sugar Research Institute has also established resistance-screening trials for ratoon stunting disease (RSD) and leaf scorch, a leaf disease that recently spread from Malaysia into Indonesia. The Institute has also embarked on an industry survey for RSD, and the disease is one of their most important. The RSD assay laboratory, established with ACIAR funding, will be central to this work.

The current project has just been extended for another two years to allow the fulfilment of several key project objectives. A key activity during the last 12 months was an end of project review, at which an extension was considered. Quite an amount of the project staff's time was initially invested in the project review, held in November 2003. Centres visited included BSES Brisbane, BSES Meringa and Ramu Sugar, Gusap, Papua New Guinea. At the review, each staff member highlighted the research undertaken in their field of expertise. Summaries were provided of the pest and disease surveys in northern Australia, Papua New Guinea, Indonesia and the Torres Strait / Cape York Peninsula areas. Entomologists and pathologists were present on each survey, with representation from each partner country on most surveys. The surveys highlighted the distribution of the major pests and diseases: this made it possible to update pest and disease records for each country and to consider strategies to prevent further movement of pests and diseases of economic threat. Some of the most important findings were the spread of smut and leaf scald diseases east from Java into the neighbouring islands, the widespread distribution of Ramu stunt around PNG, the failure to find sugarcane smut in PNG or northern Australia (apart from the Ord River area) and the incidence of unidentified forms of sugarcane mosaic in the region as a whole.
Research into a resistance screening technique for Sesamia stem borer was outlined and the use of several infestation parameters as indicators of resistance to the devastating PNG pest. Details were also provided of research into the causal agent of Ramu stunt, a severe disease of sugarcane at Ramu Sugar, PNG. Some promising leads were obtained but no causal agent has yet been assigned. The linked project investigating resistance screening techniques for sugarcane smut explored better ways of storing smut spores for field screening trials in order to save time collecting spores. A suitable technique was identified and will be used routinely in smut screening trial work.
Training was an integral part of the project and quarantine staff in both PNG and northern Australia was trained in sugarcane pest and disease symptom identification. Staff were made aware of a whole range of sugarcane quarantine issues and were given pest and disease manuals written specifically for the regions they serve (the first PNG and Cape York / Torres Strait manuals of the kind). Scientists from PNG and Indonesia also visited Australia and BSES facilities and Tully and Woodford to gain first hand experience with Australian pests and diseases. They were also trained in several new technologies.

Activities in the project for the last 12 months have included strategic surveys. In November 2004, a survey to East New Britain was conducted in order to collect further information (and samples) related to an unusual type of sugarcane mosaic. A previous survey had found this disease at Kerevat. The unusual mosaic was again located in a collection of S. edule at the NARI Research Station, but nothing was found in surrounding villages and in roadside 'wild' Saccharum species. Samples assayed at the BSES DNPRC facility failed to identify the known viral pathogens causing sugarcane mosaic, sorghum mosaic or streak mosaic diseases. There remains a need for further research to identify the causal agent of this PNG mosaic. This will be partly progressed during the life of the project but studies to specifically address determining the nature of the causal agent were not specified project objectives. A 12 day survey of east Java also sought to determine the causes of sugarcane mosaic symptoms in the Indonesian sugar industry. Collected and assayed samples highlighted the presence of several of the mosaic viral pathogens. The results will be discussed further with Indonesian scientists. A 5 day survey of sugarcane growing in Cape York tip communities was undertaken to determine the distribution of the vector for Ramu stunt - Eumetopina flavipes. The opportunity was taken to introduce a PhD student (an AQIS employee) to the pest. Her work, funded by SRDC, will greatly assist our understanding of the insect and the potential to eradicate the pest from the Australian mainland.
Research into the causal agent of Ramu stunt has been continuing and there is further evidence for the involvement of a virus as the causal agent. Research has identified a specific band in viral minipreps and a 36KDa protein in diseased but not healthy leaves. Small (isometric) spherical particles have been seen under an electron microscope in diseased tissue. This offers a solid lead in the identification of the causal agent.

Elisa equipment is in the process of being purchased for Ramu Sugar. The Ramu pathologist, who will be responsible for the assay procedure, visited BSES laboratories in May 2005 for further training in the assay procedure.

Ramu-bred varieties have entered quarantine so they can be sent to CIRAD (France) for transfer into tissue culture. This will enable them to be sent to the Indonesian Sugar Research Institute for smut resistance screening.

During the surveys undertaken in PNG, Indonesia and northern Australia, the opportunity was taken to speak to, and assist, quarantine officers and ACIAR scientists in the identification of sugarcane pests and diseases. Our visits again raised the awareness of sugarcane quarantine with these officers. Some training was also undertaken in association with an SRDC-funded project that aims to interact and train Australian quarantine staff (project leader is Mohamed Sallam from BSES). Staff visited BSES Meringa and observed the different Saccharum species found in remote parts of Australia and PNG. Presentations were also made on both endemic and exotic pests and diseases of sugarcane.