Browsing by Author "Magarey, RC"

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A review of yield losses caused by Australian and selected exotic sugarcane diseases : SRDC final report BS1725
(BSES, 1996) Magarey, RC; Croft, BJ
Yield loss studies of Australian endemic diseases, and those exotic diseases posing the greatest threat to production in Australia, are reviewed. There is a need for much research particularly in relating disease intensity with yield and in investigating the effect of varietal resistance on this relationship. It is suggested that initial studies begin with yellow spot and rust, and should include sugarcane bacilliform virus and yellow leaf syndrome when techniques for handling these diseases improve. Priorities for further research should be reviewed at the conclusion of the initial yield loss research. The effect of the important exotic disease, smut, has been well researched overseas.
Biosecurity research in PNG 2015-2017
(ASSCT, 2018) Magarey, RC; Braithwaite, KS; Kuniata, LS; Thompson, NP; Korowi, K; Samson, PR; Tom, L; Sallam, N; Derby, L
PAPUA NEW GUINEA is the centre of diversity for several species in the genus Saccharum, including S. officinarum, selections of which constituted the first commercial sugarcane varieties in Australia. Apart from providing germplasm for commercial sugarcane production world-wide, PNG is also home to pests and diseases that pose a unique and serious threat to commercial sugarcane production in Australia. These include members of the noctuid moth borer group, an oomycete causing downy mildew and the viral disease, Ramu stunt. Australian scientists have been working alongside PNG counterparts to develop management strategies that will assist with pest and disease management in PNG and enable effective preparation for a possible incursion into Australia. Over the past three years, significant outputs from the research have included a much better understanding of causal agents, specific diagnostic tests, an understanding of pest and disease distribution and faster methods for varietal resistance screening.
BS172S Pathogen Risk Analysis to Prioritise Research and Quarantine Needs of the Australian Sugar Industry. A Review of Sugarcane Diseases of Quarantine Risk to the Australian Sugar Industry, 1997
(BSES, 1997) Croft, BJ; Magarey, RC
The major diseases of economic importance to sugarcane have been identified and their quarantine risk for Australia has been reviewed. Twelve high to moderate risk quarantinable diseases were identified. Sugarcane smut must be considered the highest risk disease for Australia. It has a history of spread to new countries, is a major disease in all countries where it is present, both tropical and sub-tropical. Smut has recently spread to the island of Sulawesi in Indonesia and Indonesian plans to commence new sugarcane plantations on East Timor and Irian Jaya will increase the risk of smut entering Australia. Other diseases of serious risk are downy mildew, Fiji disease, Ramu stunt, mosaic and leaf scald. The first three are of particular concern because of their presence in Papua New Guinea and because of reported illegal imports of sugarcane cuttings and related species from Papua New Guinea into the Cairns region. Restriction of the movement of these diseases into or within Australia is essential for the continued competitiveness of the Australian sugar industry. All of these diseases should be considered quarantinable for Australia.
Chlorotic streak disease in Queensland
(BSES, 1995) Magarey, RC
Chlorotic streak is a disease of unknown etiology affecting 30-50,000 ha of caneland in Queensland annually. The disease is present in all canegrowing districts but is of greatest incidence in the Herbert River and Rocky Point mill areas. The disease is favoured by poor drainage and is spread by floodwaters. Yield losses of up to 40% have been recorded with the disease reducing germination, ratooning, stalk number, and stalk weight. It is likely to be reducing industry returns by $2-5m annually. Of concern is the likely increase of the disease with the return to wetter seasons in Queensland and with the increasing practice of re-cycling of irrigation tail waters in the Burdekin district. It is recommended that a varietal resistance screen be conducted to obtain disease ratings on current commercial varieties and that research into the causal agent be undertaken.
Chlorotic streak disease of sugarcane : SRDC final report BSS243
(BSES, 2002) Magarey, RC
Chlorotic streak is a disease recognised since 1929 and is widespread through the cane growing countries of the world. Despite considerable research, particularly in the 1940-1970 period, the causal agent of the disease is still unknown. The disease is systemic and affects germination and crop yield. It is widespread through Queensland being favoured by high rainfall and/or poor drainage. The worst affected areas are the high rainfall wet tropics and poorly drained areas in other districts. This three-year project was initiated to gain a better understanding of the effects of the disease on yield; to screen commercial varieties for resistance; to research the distribution in parts of the Burdekin River Irrigation Area (BRIA); and to attempt to identify the causal agent. Yield loss trials were planted in the Tully and Herbert districts in 2000. Varieties ranging from resistant to susceptible were included to determine the relationship between resistance and yield loss. Plant crop harvests in 2001 revealed losses of up to 60% when crops planted with stalks showing diseased symptoms were compared with crops established with stalks exhibiting no symptoms. Yield effects therefore can be dramatic with the disease. Even some resistant canes suffered significant losses, suggesting farmers should obtain the cleanest planting material they can to establish new crops. One resistant variety (Q162) suffered negligible losses. Germination was slowed, and reduced overall, by chlorotic streak disease (CSD) with the main effect being on tonnes cane/ha rather than ccs (sugar content was largely unaffected by CSD). There was a significant relationship between varietal resistance and yield (r-squared 0.56) in the Herbert trial suggesting there is a correlation between resistance and yield. Surveys of the Invicta, Pioneer, Kalamia and Inkerman mill areas revealed the presence of a greater level of CSD than known previously. The greatest level of disease was found in Q127 though other varieties were also diseased. There was a link between irrigation water source and the area affected by the disease. Where channel water was used, higher disease levels resulted compared to fields irrigated with bore water. This is not surprising because drainage water from infested fields is known to carry the causal agent and channel water contains some drainage water. Transmission studies using hydroponics were commenced to provide suitable root material for molecular assay research into the causal agent. However, no disease transmission occurred and it is postulated that a soil-borne vector may be needed to aid transmission. PhD studies at the University of Adelaide have focused on light and electron microscopy, and molecular methods of pathogen detection. This project finishes in 2003 but so far no agents have been associated with diseased material.
Chlorotic streak resistance screening in the Tully district
(ASSCT, 2016) Magarey, RC; Sevntek, K; Bull, JI; Stringer, JK; Zamora, R
CHLOROTIC STREAK DISEASE (CSD) was first recognised more than 85 years ago and is present in most cane-growing countries around the world. An important management strategy is the use of resistant varieties; past research has shown there is significant variability in resistance in the Australian sugarcane germplasm. Data are reported from a variety resistance screening trial conducted in the Tully district (2013–2015 period) that was subjected to at least five flooding events over a two-year period. Maximum ‘% stools diseased’ infection levels were over 60% in the most susceptible variety. Several current commercial varieties appear very susceptible, including Q241A and Q251A. The data show that a much higher disease incidence is evident when data on ‘% stools diseased’ are recorded rather than ‘% stalks diseased’. Recording data on a stools basis therefore may provide a shorter time frame for assessing varietal susceptibility. Crop inspections are also significantly easier using this parameter, especially in mature crops where symptom expression is often higher (and therefore desirable to undertake at this time). Major flooding events provide optimum conditions for disease transmission in field trials, as long as shoot survival is not unduly affected.
Chlorotic streak transmission and crop dynamics research
(ASSCT, 2016) Magarey, RC; Sventek, K; Bull, JI; Braithwaite, KS
CHLOROTIC STREAK DISEASE (CSD) is transmitted in water, specifically drainage, flood or irrigation water. Research showed that transmission in water was increased by the addition of oxytetracyline (Terramycin). A two-hour inoculation period, where roots were dipped in infected hydroponic solution containing the antibiotic, was sufficient to lead to significant disease levels in test plants grown in a hydroponic system. A hydroponic system incorporating no water circulation (still-hydroponics) was found more effective than one where the solution was regularly circulated. Monitoring of the disease at field sites showed that disease levels build up over time and that different lengths of inundation associated with flooding events may lead to uneven distribution of the disease in a commercial crop.
Effects of pachymetra root rot and nematodes on some elite sugarcane clones in Australia
(ASSCT, 2016) Bhuiyan, SA; Croft, BJ; Wong, E; Ogden-Brown, J; Turner, M; Parfitt, R; Magarey, RC; Bull, J; Cox, MC
PACHYMETRA ROOT ROT and nematodes are the two most important soil-borne pathogens of sugarcane in Australia. An experiment was established in Yandaran, Queensland in grey forest soil with high Pachymetra spore counts (>100 000 spores/kg). Fifteen elite varieties and one advanced clone, from pachymetra root rot susceptible, intermediate and resistant categories, were planted in the experiment. The experiment was maintained until the second ratoon crop and Pachymetra and nematode populations were assessed in each crop. In addition, the incidence of smut was recorded before harvesting. Cane yield (TCH), commercial cane sugar (CCS) and sugar yield (TSH) were also measured in each crop. Pachymetra spore counts remained significantly lower in resistant varieties compared to susceptible and intermediate varieties until the second ratoon. In intermediate and susceptible varieties Pachymetra spore counts increased substantially, in particular, in second ratoon. In intermediate varieties such as Q232A and Q208A Pachymetra spore counts increased more than three times from plant crop to second ratoon. Numbers of nematodes, in particular root-lesion nematode, more than doubled in the second ratoon crop compared to the plant and first ratoon crops. Only Q248A had significant levels of smut, with 25% and 30% infected plants in the first and second ratoon crops, respectively. Yield reduction was substantial in the second ratoon compared to the plant and first-ratoon crop. Sugar yield decreased by 45% in the second ratoon compared to the first ratoon. Mostly, poor or negative correlations were observed between both Pachymetra spore counts and nematode numbers and yield.
Enhancing resistance to yellow spot disease": SRDC final project report BSS245
(BSES, 2003) Magarey, RC
Yellow spot is a leaf disease caused by the fungus Mycovellosiella koepkei. Although known in Queensland since 1950, some facets of the disease have never been adequately researched. Yellow spot principally, but not exclusively, affects cane in the wet tropical coastal areas of Queensland. The disease is favoured by warm wet conditions, usually being observed during and shortly after the wet season (March-May). Up to 50,000 ha may be affected in Queensland in years of above average rainfall. Little yield-loss research had previously been conducted and there was a need to review the current breeding strategy to ensure adequate resistance in commercial varieties.Research associated with this project aimed to:1. determine yield losses resulting from the disease;2. assess the current levels of resistance in the Australian germplasm;3. make recommendations regarding the current breeding strategy.Research outputs impinged on each of these areas. Resistance was assessed on the basis of leaf areas diseased at the peak of the disease epidemic (April-May). Assessment of parent canes and commercial cultivars suggested there is less resistance to yellow spot than to the other important diseases in northern Queensland, including Pachymetra root rot and orange rust. This is a cause for concern and warrants consideration by breeders and pathologists. There were only minor differences in the proportion of resistant, intermediate and susceptible parents sourced from each district (Northern, Herbert, Burdekin, Central and Southern).Yield-loss research with fungicides showed that yellow spot may reduce the CCS of susceptible clones by up to 2 units early in the harvest season. In resistant clones, as expected, losses were negligible. Selection trials in the breeding program (FATs) were also utilised to assess yield losses and the influence of clonal resistance on losses. This approach again showed that yellow spot may reduce yields significantly, especially in the wetter years. In the 2001 season, yellow spot was of greater significance than either orange rust or Pachymetra root rot. Losses of up to 20% in cane and sugar yields were observed.An analysis of the conditions required for spore germination showed that high relative humidity (>99%) and relatively high temperatures (20-30?C) were needed for spores of M. koepkei to germinate. This correlates with disease incidence, since it is most severe on the wet tropical coast. An analysis of Bureau of Meteorology data for Cairns, Townsville, Mackay and Brisbane indicated that Cairns was the most favourable site out of these three; again consistent with disease observations. Further studies on environmental conditions favouring the disease, and the analysis of longer-term weather data may facilitate an assessment of the probability of severe disease outbreaks in cane-growing areas. By linking this with yield loss research, it may be possible to accurately identify the level of resistance needed in commercial canes to minimise commercial losses.
Epidemiology studies into sugarcane smut : SRDC final report BSS302
(BSES, 2010) Magarey, RC
The objective of this project was to: Optimise industry transition from susceptible to resistant commercial varieties, with minimal losses resulting from direct or in-direct crop effects, thus maximising industry profitability.
Estimating disease-associated yield losses in breeding selection trials - Endemic diseases; Pachymetra root rot, orange rust and yellow spot
(BSES, 2007) Magarey, RC
Previous work has shown that plant improvement stage 3 selection trials can be used to assess the relationship between yield and disease resistance with particular Queensland endemic diseases - principally Pachymetra root rot, yellow spot and orange rust. Results provide a means for fine-tuning the plant improvement program - ensuring that commercial varieties have just the right level of resistance to maximise high yielding ability while minimising disease-associated yield losses.In this study, data from 2003-series stage 3 (FATs) trials in northern and central districts were studied to determine the relationship between resistance and yield for Pachymetra root rot and orange rust. As yellow spot only occurs in the high rainfall areas of northern Queensland, analyses for this disease were restricted to this region only. Brown rust was to be included in the study but the difficulty is assessing disease resistance in FATs, and the lack of disease, made obtaining data to brown rust impossible. Additional data were available for Pachymetra root rot for northern series trials (1995-2004) providing more detailed information for this disease.
Final report on SRDC project CLW002 (previously CSS02 & CSS2S): The role of root growth and activity in determining sugarcane productivity
(1999) Magarey, RC; Nable, R; Reghenzani, J; Smith, J; Berthelsen, S; Grace, D; Robertson, M
When the current project was initiated, poor root growth and activity were widely believed to be a major constraint to sugarcane productivity. However, there was no technology available to assess whether or not root growth and activity were constraining cane productivity. The project was established to examine the relationship between root growth and activity and sugarcane productivity. The strategic information to be generated was expected to provide the basis for estimating the potential value of overcoming poor root growth and/or activity by managing various soil constratints such as soil pathogens, poor soil structure, or low soil fertility. Initially, the objectives of CLW002 were to: quantify the relationship between root system characteristics and crop productivity; assess the methods for measuring root activity as indicators of root system constraints on crop productivity - with particular emphasis on methods that would allow remote assessment of root activity.
Identification of unknown root pathogens responsible for sugarcane yield decline : SRDC final report BS73S
(BSES, 1996) Magarey, RC
Sugarcane yield decline (YD) is characterised by poor root development ( a lack of fine root growth, root discolouration) and poor root health. Previous YD research implicated the involvement of unrecognised pathogens in the growth constraint. Research in this project attempted to determine the etiology of YD using various approaches. Electron miscroscopy highlighted the poor root surface characteristics in YD-affected roots and showed that soil pasteurisation greatly improved the root surface condition.. Transmission experiments demonstrated that very small quantities of either YD roots or soil extracts could lead to major growth depression and roots similar to YD, even in a non-degraded rainforest soil. Biocide studies showed that some general fungicided (mancozeb, maneb, zineb, benomyl, chlorothalonil, and anilazin) eliminated poor root health associated with YD, and implicated soil fungi in YD. Multiple regression analyses conducted on data from glasshouse experiments with diverse treatments also suggested that soil fungi were intimately involved in YD. Fungal isolates from sugarcane root systems and pathogenicity testing showed that dematiaceous and white sterile fungi could reduce sugarcane root growth and were probably significant contributing factors to YD. Studies into the unfluence of mycorrhizae (VAM) on sugarcane growth were initiated and VAM were shown to be common in sugarcane soils. A comparision was made between apple replant disease and YD and many Similarities observed. Research into other replant diseases should be accessed to assist YD investigations. Further research should seek to develop an assay for dematiaceous fungi and to study the influence of management strategies on these organisms. The effect of VAM on sugarcane growth at high P and the effect of various management strategies on the soil biological community are two important research areas.
Incidence and economic effects of ratoon stunting disease on the Queensland sugarcane industry : ASSCT peer-reviewed paper
(ASSCT, 2021) Magarey, RC; McHardie, R; Hession, M; Cripps, G; Burgess, D; Spannagle, B; Sutherland, P; Di Bella, L; Milla, R; Millar, F; Schembri, A; Baxter, D; Hetherington, M; Turner, M; Jakins, A; Quinn, B; Kalkhoran, SS; Gibbs, L; Ngo, C
Ratoon stunting disease (RSD) has had a significant influence on productivity and profitability in the Australian sugarcane industry for at least the last 76 years. There have been few attempts to objectively quantify the incidence and economic influence of the disease across the industry. Most Cane Productivity Service (CPS) groups routinely monitor RSD in plant sources and, in some cases, in commercial crops. Surveys by 12 Queensland CPSs were conducted in 2017- 2020 with sampling of different proportions of commercial crops (5-25% of farms) in each region. The latest molecular technology was adopted to assay samples. RSD incidence varied between 0 and 60% in commercial crops and 0 and 41% in plant source inspections. The data suggest that implementation of the three pillars of RSD management (disease-free seed-cane, equipment sanitation and planting into fallow ground devoid of volunteers) were essential to minimise RSD incidence. Failure to adequately address any one of these pillars often compromised RSD management. An economic analysis suggested that RSD led to an annual loss of $25m in the study areas in the 2019 crop. This is significant, but it is unlikely to be the largest single disease constraint on productivity.
Innovation in disease management; where to next : ASSCT peer-reviewed paper
(ASSCT, 2019) Magarey, RC
New technologies offer considerable scope for the refinement of disease management in the Australian sugarcane industry. While resistant cultivars, disease-free plant sources, crop termination and quarantine have provided a strong foundation for good disease management, the development of new technologies offers the possibility to make changes to data accumulation, analysis and application to industry. DNA- and NIR-based assay technology, remote sensing, drones, data digitisation, GIS and information databases offer the ability to capture huge additional amounts of relevant field data, enabling a better understanding of disease issues and the management required to minimise losses. This will also enable targeted extension of management strategies to individual farmers and industry sectors. Automated pathogen assays may also be possible, centred on the sugar factory. Step changes in disease management are likely in the next 5-10 years.
Inspection of Torres Strait Islands for pests and diseases of sugarcane
(BSES, 1996) Magarey, RC
This visit between 1-4 July 1996 proved most useful in assessing the pest and disease status of the Torres Strait islands. Significantly there were first records of schlorotic streak, Ramu streak, Sesamia borer, and hybrid Saccharum material in the region. It is imperative that effective sugarcane quarantine occurs in the region to limit the spread of these pests and diseases and the Saccharum material. Ramu streak and Sesamia borer could significantly affect crop production in Australia. On the other hand, the disease status of the hybird material is uncertain. The presence of continental Australian diseases in hybird material poses a significant threat to PNG. In future visits, the disease status of this material should be further investigated.
Integrated disease management of sugarcane streak mosaic in Indonesia : final report 2012/083
(Australian Centre for International Agricultural Research (ACIAR), 2019) Magarey, RC
Sugarcane streak mosaic (SCSM) caused by sugarcane streak mosaic virus (SCSMV) is a relatively recently recognised disease of sugarcane that is now widespread through S.E. Asia and widely infecting commercial crops, both in terms of incidence and in the percentage of plants infected within individual fields. Crop losses, though not spectacular in individual plants, is very significant since whole crops are very often affected meaning that accumulated smaller losses in individual plants leads to very significant losses for cane farmers. A number of aspects related to the disease were unknown at initiation of this research, including: distribution across Indonesia (Sumatera, Sulawesi, and the eastern archipelago); transmission mechanisms (mechanical or insects or planting material only); the epidemiology and speed of spread; crop resistance; sensitive, specific and cheap detection technologies; and an effective integrated disease management (IDM) strategy. All these points were addressed in associated research activities.
Molecular assay of major soilborne sugarcane pathogens for better exploitation of commercial varieties : final report 2016/047
(Sugar Research Australia Limited, 2018) Magarey, RC
A commercial assay service, based on specific DNA tests for soil-borne pathogens, has been developed for various cropping industries by the South Australian Research and Development Institute (SARDI), Adelaide. A unique feature of the DNA testing service is the ability to assay 500 g of soil in a single test, a breakthrough made possible by SARDI researchers, enabling the reliable, sensitive detection of root pathogens. The assay service now provides feedback on a range of deleterious, as well as beneficial, organisms in the grains and horticultural industries across southern Australia and in cereals in NSW and southern Queensland. This has provided important decision-making information for the application of better soil-borne disease management strategies. The service is now expanding further into northern Australia. Specific DNA assays were developed in this project for the major root pathogens / parasites in the Australian sugarcane industry (Pachymetra chaunorhiza and Pratylenchus zeae; Meloidogyne species tests were developed much earlier. The results from these assays were compared to traditional manual assessment. There was very good agreement between manual counts and the DNA results for Pachymetra chaunorhiza, and the two major nematode root parasites, Pratylenchus zeae (root lesion) and Meloidogyne species (root knot). This suggests that the SARDI laboratory could provide an assay service for these organisms in the sugarcane industry. Advantages of the SARDI service include the ability to rapidly assay large sample numbers (>80 in a batch), to be able to apply multiple tests to single soil samples, and to potentially do this testing at a reduced cost compared to the normal manual tests. In addition, the molecular nematode assays do not require nematode viability to be as carefully maintained for accurate assay results. Disadvantages of the molecular assay method are the potential for increased assay costs with small sample batch sizes; a slightly less-sensitive assay for Pachymetra chaunorhiza (compared to the traditional counting method) and potential slower turnaround times with limited sample numbers flowing through the laboratory. Southern experience suggests that additional tests will be added once the service is initiated, with better all-round information on soil biology resulting. A recommendation from the project is for SARDI to be contracted to undertake the molecular assays while the Tully soil assay laboratory maintains assay recommendation and data warehousing roles. Results from this project were extended to industry, which is now in a place to adopt the assay service provided by SRA / SARDI.
Pachymetra chaunorhiza as a factor involved in stool tipping in North Queensland : SRDC final report BS33S
(BSES, 1991) Magarey, RC
The objectives of this project were to determine the soil and environmental factors favouring Pachymetra root rot, and how these contributed to stool tipping in the moderately resistant and susceptible varieties Q117 and Q124.
Pachymetra root rot surveys of the Tully district update 2018 : ASSCT peer-reviewed paper
(ASSCT, 2019) Shannon, GJ; Magarey, RC; Macgillycuddy, L; Stringer, JK; Lewis, M
Pachymetra root rot is a soil-borne disease that impacts all sectors of the Australian sugar industry. The disease attacks the root system of sugarcane crops, affecting yields and leading to stool loss and shortened crop cycles, thus impacting the farming, harvesting and milling sectors. Monitoring the disease is, therefore, important so that optimised management practices are adopted, so bringing benefits to the entire value chain. A survey of the Tully district conducted in 2004 showed that pachymetra root rot was widely distributed across the Tully mill area; a second survey undertaken in 2013 sought to determine trends in disease incidence after some significant changes occurred in the cultivar mix. Crop resistance had shifted significantly with a change in cultivar resistance and there was a consequent increase in disease severity. Financial losses from reduced yield were estimated at $5.5 million in 2013; this compares to just under $1.0 million in 2004. This paper reports on a third survey in 2018 that is a five-year update to provide snapshot of the status of this disease in the Tully sugar industry. While the disease is still widespread, its severity has decreased with financial losses estimated to be $3.5 million.