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. 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.
The application of blockchain technology in the Queensland sugar industry offers improved traceability and a platform to show validated provenance of sugar produced in Queensland. By using Smartcane BMP and blockchain technology, CANEGROWERS is seeking to provide the provenance for sugar, increase market access and provide greater value to growers and the market. CANEGROWERS worked with KPMG Australia to prototype the application of a blockchain platform to prove the amount (on mass balance) of sustainable sugar entering the supply chain from Australia. Industry stakeholders were consulted to develop a Queensland sugar-industry supply-chain map to show how sugar could be digitally represented and traded across the supply chain. A data taxonomy was created to define and identify data so linkages could be created for traceability from the grower to the end-user. The data taxonomy was used to build the blockchain prototype on the KPMG Origins blockchain platform. The research showed that developing a digital supply-chain platfoim using blockchain technology was possible and could improve the visibility of Queensland's sustainably produced sugar. This has the potential to leverage market access for sugar, strengthen the industry against global competition, identify means of improving value for growers, and ensure shifting regulatory and consumer changes are addressed. This was the first time blockchain has been developed for the Queensland sugar industry. Future work has been scoped to test end-to-end traceability of Smartcane BMP-accredited sugar through the supply chain using the KPMG Origins platform.
In 2019, the Australian sugarcane industry conducted a month-long demonstration with 12 trials to determine the commercial viability of harvesting best practice. Initiated by a small group of innovative growers and contractors from the Herbert region, the concept of a commercial demonstration sought to determine both agronomic and economic impacts of adopting HBP, including the assessment of possible yield gains without having a detrimental impact on extraneous matter, and economic implication for growers and harvesting contractors arising from revenue and harvesting cost changes. Two Herbert harvesting contractors participated in the demonstration comparing their standard harvesting practices to Sugar Research Australia Harvesting Best Practice (HBP or recommended practice). The results identified an average 4.8 t/ha increase in yield with no additional increase in extraneous matter for the recommended setting. A comprehensive economic analysis was conducted on each of the trials. Detailed harvesting costs and operational information, including machinery, labour, and fuel data, were collected from the respective harvesting operations. Harvesting costs and levies were $37/ha ($0.07/t) higher for the recommended setting due to higher yields, reduced harvester ground speeds and lower extractor fan speeds. Despite the higher harvesting costs, recommended settings obtained significantly higher total revenue ($151/ha, +4.7%). This resulted in an overall net benefit of $114/ha in the adoption of recommended settings (based on a 4.4% higher net revenue calculated as total grower revenue minus harvesting costs and levies). The Herbert demonstrations have proven instrumental in the acceptance of harvesting best practice for the region. The results again confirm that adapting and aligning commercial-scale harvesting practices to crop and paddock conditions have positive impacts on both yield and economic outcomes.
Ratoon stunt (RSD - Leifsonia xyli subsp. xyli - Lxx) is considered to be a manageable disease, provided the recommended integrated management strategy is followed. Once a field has been planted, the main risk of spread is at harvest. While it is possible to easily and effectively decontaminate cane knives during the harvesting operation, mechanical harvesters pose more of a challenge. An effective disinfectant and a suitable method are required to decontaminate mechanical harvesters and to minimise the risk of RSD spread, particularly between fields and farms. A foaming quaternary ammonium compound (QAC) containing benzalkonium chloride and didecyl dimethyl ammonium chloride, was effective against Clavibacter michiganensis (used as an indicator bacterium) and Lxx in in vitro and in vivo experiments, respectively. This disinfectant was identified as a suitable alternative to the current industry standards, Jeyes Fluid and methylated spirits, for minimising the risk of RSD spread on farm implements. Three field trials confirmed that mechanical harvesters transmit RSD from infected to healthy stools at harvest. The procedure used to decontaminate the harvesters took two people up to 40 minutes to complete. While it reduced the spread into a healthy cane in the trials, it did not eliminate the risk entirely. Management strategies to accommodate this risk will need to be implemented.
Sugarcane juice clarification is integral to the raw sugar manufacturing process. A comparative investigation between three short retention time (SRT) clarifiers of different designs, operating in parallel at one Louisiana (LA) sugarcane factory, was undertaken to evaluate their performance across a processing season. The factory used a hot lime clarification process in one Fletcher Smith clarifier and two LLT clarifiers; LLT1 had 9 turbulence reduction devices (TRDs) and LLT2 had 18 TRDs. Five samples of Hot Limed Flashed Juice (HLFJ) and Clear Juice (CJ) were collected each day, taking into account the retention times across each SRT clarifier, with a 30 min interval between samplings. Sampling periods were repeated six times during the 2019 processing season, with 120 samples collected. Overall, the LLT clarifiers performed slightly better than the Fletcher Smith clarifier, with slightly lower CJ turbidity, CJ calcium and phosphate values, and greater removal of turbidity, calcium, and phosphates. This may be explained by (i) the more stable flow of the juice fed into the LLT clarifiers and/or (ii) the addition of flocculant in each TRD of the LLTs, which meant the flocculant was more uniformly distributed into the juice in a high-velocity zone and guaranteed its effective mixing with the juice. Comparing the performance of the two LLT clarifiers, there was no statistical difference between them. However, the LLT1 performed slightly better than the LLT2, which may be a result from the clarifiers processing a different juice flow rather than design. As the three clarifiers processed the same HLFJ, it allowed for a comparison of total sucrose losses across clarification. Season average values of sucrose losses measured using high performance liquid chromatography across the Fletcher Smith, LLT1, and LLT2 clarifiers were 0.210, 0.363, and 0.336%, respectively, but not significantly different at p<0.05. The Fletcher Smith clarifier had slightly lower sucrose losses than the LLT clarifiers, resulting from its relatively lower residence time. Overall, the average value of sucrose losses for all three clarifiers in this factory was 0.306%, equivalent to 605,868 lbs of raw sugar, and represented a profit loss of US$152,981 and $0.20/TC for the whole season.
For sweetest things turn sourest by their deeds: Lilies that fester smell far worse than weeds. William Shakespeare (Sonnet 94)
An equitable payment system between sugarcane and sugar beet growers and the factories that process the crops underpins the sector's viability. This study illustrates the diversity of payment systems that proliferate in both the cane and beet industries, with particular reference to those employed in 29 WABCG (World Association of Beet and Cane Growers) member countries. These vary from the government moderated systems (e.g. Morocco, Turkey, India) to where growers directly participate with sugar companies to fix their crops' price (Australia, Nicaragua, UK). With advances in process conversion technologies which have helped realise increased revenues for factories from bagasse, pulp and molasses, there has been a growing acknowledgement in crediting growers (in Eswatini, Morocco, Mauritius, Belize, Mexico) for these by-products. This study highlights in particular changes to the payment systems made over the last seven years in Colombia, in Mauritius and in Eswatini, in Nicaragua, in the United Kingdom and in Uganda.
Sugar beet (Beta vulgaris L.) is an important cash crop and is one of the main sources of sucrose, accounting for more than 30% of sugar production worldwide. Sugar beet production is often threatened by soil-borne pathogens, which can attack the roots at all stages of sugar beet development, disrupting entire sugar beet fields and causing severe yield losses. One of the most problematic root diseases in sugar beet is Aphanomyces root rot, caused by the oomycete Aphanomyces cochlioides. This pathogen is globally widespread and is responsible for drastic economic damage in all major sugar beet producing countries. Sources of resistance are limited, and no effective control measures are currently available. Further studies on host-pathogen interactions are needed to improve disease management, and novel breeding tools are urgently required. Moreover, the increasing knowledge of biological control agents could be employed to develop integrated disease management strategies to minimize the damage caused by A. cochlioides. In this review, we provide an overview of A. cochlioides biology and infection processes focusing on disease management and new insights for future control strategies.
ICUMSA 45 is a term that is frequently found in trade descriptions of white sugar, but its meaning is not clear. There is an implication that the term refers to a certified product or quality, but the use of the ICUMSA 45 term is not well-defined or consistent. A review of relevant and recognised international standards describing white sugar (Codex, EU regulation) clearly shows that there is not a product defined as ICUMSA 45. Recommended methods to determine white sugar quality are most often those defined by ICUMSA, but ICUMSA does not certify products, so use of the ICUMSA name in a product is inappropriate. The lack of an official, globally defined meaning for ICUMSA 45 is concerning and needs to be addressed.
Farm data indicates that the suppression of weeds by the crop canopy should play a more integral role in weed management strategies in sugar beet. Targeting better plant establishment, variety selection and ensuring sufficient nutrition for the developing crop can help the crop suppress weed growth. Selecting seed rates in relation to soil type and expected weed burden can help ensure optimum plant populations. Different variety growth habits are linked to the levels of weed suppression, especially of taller weed such as fat hen, and maybe a relevant consideration for growers. Additionally, ensuring sufficient nitrogen is available for early and rapid canopy development. Band placement of some of the nitrogen has been linked to improved early canopy growth.
Currently, there are just under 100K hectares of sugar beet grown in Great Britain (G.B) by around 3000 growers based predominantly in the East of England. Herbicides account for approximately 20% of sugar beet growing costs in England and nearly 70% of spray costs'. Without weed control, yields can be reduced by 90 t/ha depending on the weed species present. Recent years have seen the demise of herbicide actives available to control annual broad-leaved weeds (ABLW's) in beet within G.B., and of those actives remaining some are still under threat of losing their approval. Beet growers in England need to obtain optimum performance from the 8 conventional and 2 acetolactate synthase (ALS) herbicides that are currently approved for use (Table 1) and consider all available options to prevent weeds from competing with the crop.
To shorten the current lengthy selection process in sugarcane breeding and to accelerate genetic gain, Sugar Research Australia is implementing a range of novel breeding strategies and selection tactics. One strategy is to rapidly evaluate the progeny of elite crosses in replicated trials without passing through the traditional Stage 1 trials. However, insufficient planting material hinders its adoption. A seed-based in vitro propagation system has been developed for sugarcane in which sodium hypochlorite (bleach) and plant preservative mixture (PPM (TM)) were used in the sterilisation of seeds and seedlings, as well as in the treatment of infected seedlings. The system had been successfully implemented to propagate over 1000 clones of the elite cross Q208 x CP74-2005, for a Stage 2 selection trial. The new system, a first for sugarcane, is more cost-efficient, providing three times the number of clones as in the seedling-based micropropagation system with the same input of resources. This innovation will shorten the selection cycle of proven elite crosses by up to 3 years, accelerating the delivery of new varieties.
Herbicide usage reduction is called for in the EU's Green Deal and Farm-to-Fork strategy. New developments in autonomous weed control have led to the first robots for practical use in organic farming, such as the sowing and weeding robot FarmDroid FD 20. They can significantly reduce manual weeding by hoeing not just between the rows, but also within the rows. However, hoeing is not an option where weeds are within a short distance of a crop plant to avoid possible damage to it. Under these circumstances, the use an intelligent spot-spray system such as the one developed by Amazone is a suitable option. In a field trial at the Sudzucker's experimental farm in Kirschgartshausen (Mannheim, Germany) in 2021, broadcast herbicide spraying was compared with autonomous hoeing with or without spot spraying. Findings indicated that while broadcast spraying was the most effective treatment in weed control, there were no significant differences in beet yield between the treatments. The sprayed area could be reduced by 90 % owing to the spot spraying. Further, hoeing and band spraying resulted in the reduction of herbicide usage by 50 - 60 %.
Undetermined sucrose loss is a serious problem in raw-sugar manufacturing. Laboratory deterioration experiments were conducted at ambient temperature using factory mixed juice (MJ) and filtrate (FIL). Well-known metabolic products, including mannitol, lactic acid, polysaccharides, oligosaccharides and organic acids, were detected. Unexpectedly, methanol was found in both the untreated and deteriorated juices and is suspected to be caused by the action of microorganisms on the pectin present in sugarcane juice. The deterioration rate of filtrate was generally slower than that of mixed juice, but the formation of exocellular polysaccharides was significantly higher. The mannitol concentration was a good indicator to predict sucrose loss in MJ but not in FIL. It is suggested that an evaluation of the use of biocides, particularly in the filter station, to reduce the negative impact of polysaccharides due to filtrate recycling to mixed juice, should be undertaken.
