To demonstrate the influence of the diesel engine’s speed over the energy consumption and performance of large lateral move (LM) irrigation machines, 10 field tests were conducted on four LMs on the Darling Downs of South East Queensland. A key objective of the research was to identify if a relationship existed between the performance (uniformity) and energy consumption of the machines, allowing an optimum point to be established.

The main findings of the field testing and analysis were: 1) in general, the emitter discharges were found to decrease with increasing distance from the supply pump; 2) the uniformity was found to decrease in all cases when the engine speed decreased the total flow rate below that of the design; 3) the energy consumption increased with each increase in engine speed; 4) the energy consumed per ML of water pumped, and hence energy cost per year, increased significantly with each increase in engine speed; and

5) a relationship was found to exist for two of three LMs whereby the highest uniformity was achieved at engine speeds that put the pump operating point closest to that of the design.

This project funded bronze sponsorship of the Science Protecting Plant Health 2017. With delegates from around the world, severalfrom Australasia, Science Protecting Plant Health 2017 offered an unparalleled opportunity to showcase CRDC's research, products and services to key players and decision-makers on the world stage. Conference themes focused on the latest science, research and practice from leaders in their fields.

This international event displayed the latest research on plant biosecurity and pathology

science and practice from leaders in their fields and included a strong plant pathology stream as

it incorporated the 21st Australasian Plant Pathology Society conference.

Plant health is an issue of priority and concern to government, agricultural industries and

environmental organisations globally. As international trade in agricultural products grows,

the changing threats of plant pests and diseases mean that meaningful scientific exchange

among researchers and industry is vital to address new challenges to plant health and crop

protection.

The overall objective to provide a high quality scientific conference for plant health

researchers and stakeholders to:

» Learn, workshop, network and exchange knowledge on agricultural and

environmental biosecurity and plant pathology

» Facilitate engagement and exchange of ideas between researchers and the endusers

of their research, such as industry and regulators

» Provide a unique opportunity to showcase the diversity of science, innovation and

new technologies and knowledge that is protecting plant health around the world

» Build cross-disciplinary networks across all biosecurity and plant pathology

related disciplines

» Help Australia, partner organisations and sponsors, as world leaders in

plant pathology, agricultural and environmental biosecurity research and

management to support and stimulate collaboration, innovation and

networksew technologies and knowledge that is protecting plant health around the world

» Build cross-disciplinary networks across all biosecurity and plant pathology

related disciplines

» Help Australia, partner organisations and sponsors, as world leaders in

plant pathology, agricultural and environmental biosecurity research and

management to support and stimulate collaboration, innovation and

networks

Fusarium oxysporum f.sp vasinfectum (FOV) has merged as a very serious pathogen of cotton, which apparently lacks good sources of endogenous resistance to Fusarium wilt. In contrast, there are several well defined genes in tomato for resistance to the related pathogen Fusarium oxysporum f.sp lycopersici (FOL) and tomato has the best characterised system of plant interaction with Fusarium. The tomato I-2 gene for resistance to FOL has been cloned and found to encode a coiled-coil-nucleotide-binding site- leucine-rich repeat(CC-NBS_LRR) protein similar to proteins encoded by a number of resistance genes to various plant pathogens in various plant species.

Under previous CRDC funding, we engineered the I-2 gene to allow its expression/over expression under the control of a strong constitutive promoter (the 35S from cauliflower mosaic virus) and, in collaboration with CSIRO Plant Industry, attempted to produce 35S:I-2 transgenic cotton. However, we were unable to generate transgenic cotton lines containing 35:SI-2. We interpreted this result to indicate that over expression and/or inappropriate temporal or spatial expressions of the I-2 protein caused inappropriate activation of cotton defence mechanisms leading to cell death. Interestingly, this finding is consistent with the expression of some disease resistance genes in different plant species eg. the flax L6 resistance gene expressed in tobacco causes the constitutive activation of tobacco plant defences.

We continued to test I-2 function in cotton by Agrobacterium-mediated transient expression of the 35S:I-2 gene in cotton leaves. We found that over expression of the I-2 in cotton leaf tissues resulted in necrosis consistent with activation of cotton defences. Again, this finding is consisitent with results that would be expected following over expression of an active resistance gene. More importantly, it indicated that the I-2 was biologically active in cotton.

Given that over expression of I-2 caused inappropriate activation of cotton defence mechanisms, we explored the possibility of using the I-2 promoter in place of the 35S promoter. A glucuronidase (GUS) reporter gene was fused to the I-2 promoter and the fusion construct was expressed in hairy roots of cotton induced by Agrobacterium rhizogenes. Staining for GUS activity showed that the I-2 promoter was active and showed a similar pattern of expression in cotton to that in a tomato ie: in cells adjacent to to the vascular tissues of the root. We therefore made a DNA construct with the I-2 gene driven by its own promoter for use in cotton transformation experiments.

following the conclusion of our previous CRDC funding, we proceeded, in collaboration with the CSIRO Plant Industry, to produce transgenic cotton with the I-2 gene under the control of its own promoter. Twenty two T0 lines were produced, with 9 of these identified as independent lines. In this project, we have analysied the progeny of these primary transformers to determine how many transgenic loci are present. Many of the primary transformants carry multiple I-2 loci. All I-2 lines were screened for their resistance/tolerance towards FOV in glasshouse trials. Whilst the preliminary results from an initial glass house trial were encouraging, later FOV bioassays demostrated that the possession of the I-2 gene appeared to have no effect on resistance/tolerance in cotton against FOV.

The presence of an active interaction between plants and microbiological life in soil has been accepted for many years. This interaction is particularly important in the rhizosphere, where plant exudates and other rhizodeposits directly feed the microbial population, which in turn is responsible for nutrient cycling, production of growth promoters, disease suppression, agrochemical degradation and occasionally development of pathogenicity. These factors are important to plant health and productivity. However, the difficulties of studying such interactions in the soil and the inability to grow the majority of soil microorganisms in the laboratory (for example, at present <10% of microbial life in soil is cultured in the laboratory) have resulted in limited research in this area. Up to 40% of photosynthetically fixed carbon is released by plant root.

With the introduction of genetically modified (GM) crops into agricultural production systems public concern resulted in renewed interest and research into the impacts of new varieties of cotton on plant growth, productivity and environmental health. (Gupta and Watson, 2004; Brookes and Barfoot, 2005). Results from the previous research indicated that although some differences exist between rhizosphere microbial communities of non-GM and GM crops, they were not specifically identified as being caused by the expression of the introduced transgenic material alone. The results did, however, imply that cotton variety groupings were more likely to be associated with differences in the rhizosphere microbiota. In this project, two years of field and laboratory trials were conducted to assess what level of influence cotton varieties have on their associated soil microbiota involved in key functions and if there might be potential to influence these as a management tool.

Results demonstrated that there is a very strong relationship between the bacterial communities that develop in the cotton rhizosphere from the start of the season. Although there were seasonal based differences in the populations of rhizosphere microbial communities, a clear varietal separation was observed. Differences in the genetic and catabolic diversity of microorganisms between varieties suggest that rhizosphere microbial communities may be adapted to the quantity and quality of root exudates from cotton plants. The released plant products act as selective carbon and nutrient sources enriching a select group of microbial communities. These diverse microbial communities demonstrated shifts in several functional capabilities, particularly relating to N cycling e.g. N mineralization, free-living nitrogen fixation. This could form the basis for development of lower input and more biologically orientated and efficient cotton farming systems. With the current increases in fuel and fertilizer costs such systems are likely to be beneficial in the near future, but more work would be required to capitalise fully on this potential.

Black Root rot (Thielaviopsis basicola) BRR is a major threat to cotton production in southern and central NSW. It has a wide host range of more than 230 species of plants (Pereg 2013). The fungus survives for long periods in the soil as resistant resting spores. Infection of cotton is favoured by soil temperatures below 20 °C, which is normal at planting time in these cooler regions. Research in the USA has shown that severe disease symptoms result when the population of the black root rot fungus reaches 100 spores/g. It delays crop development in a region which already has a constrained growing season.

Populations of 600–700 spores per gram of soil have been found in some Australian cotton fields. Black root rot fungus does not kill seedlings by itself, however severe infection will render cotton more susceptible to other seedling diseases such as Pythium and Rhizoctonia. Stand losses of 30% or more are common from combinations of these seedling diseases. Seedlings affected by black root rot are stunted and slow growing. In effect, the disease ‘steals’ time from the crop leading to delayed maturity and yield loss. As weather conditions and temperatures improve, infected cotton crops will recover but in poor establishment conditions, yield reductions of 25–50% have been attributed to severe black root rot. The use of Woolly pod vetch as a green manure crop has been shown in previous research to reduce the impact of BRR in fields. This project aims to investigate the use of a bio fumigant crop such as Woolly Pod Vetch based on previous research. The concept of biofumigation involves planting a crop that releases compounds that are toxic to pests or pathogens in the soil. It involves growing and harvesting the biofumigant plant as either a rotation crop or as a sacrificial crop that is sprayed out and incorporated (brown manuring) or freshly incorporated (green manuring) into the soil prior to planting cotton. The effectiveness of biofumigation relies on the bulk of the crop being incorporated at least four weeks before planting cotton to allow breakdown of the material so there are no phytotoxic effects on the following cotton crop. A number of crop types have been trialed over the years as biofumigant crops including woolly pod vetch, mustard, canola and fodder radish. Three seasons of trials on different fields in northern NSW resulted in a 28–70% reduction in black root rot disease severity from Indian mustard and a 24–61% reduction from woolly pod vetch (Nehl 2004 )

This capital item funding is for the purchase of the small tractor and trailer. It is anticipated by the researcher, that this equipment will greatly assist with spraying and minor tillage operations associated with field trials. Previously the project relied on farm staff for transporting and spraying of field trails on research farms and growers properties. This often coincided with other farm staff operations, which made it difficult to co-ordinate for timeliness of operations.

Ownership of the equipmeenables field trialsto be progressed more efficiently and effectively, particularly where a number of spraying applications need to occur (eg. double knock – second knock timing trials). This purchase will save approximately $1500 - 2000/year by not having to pay farm staff salary and operating costs.

The annual qualitative and quantitative survey project measures the impacts and outcomes of research and production critical to the Australian cotton industry. Crop Consultants Australia (CCA) has collected quantitative and qualitative data for the industry since the early 1990s. The data helps the industry to better understand the impact of research and extension, technology adoption, farming practices and product usage as well as identifying new issues and opportunities.

This project collected and provided quality quantitative and qualitative datasets of good geographical representation (coverage of Australia’s cotton production area) relating to economic, environmental and social factors of Australia’s cotton industry for the seasons 2014/15 – 2016/17. The data collected each year and provided to CRDC is able to be compared with data from other years to determine progress on various issues and changes in management practices.

The data provided to CRDC is utilised by industry for benchmarking, trending and research purposes.

Until 2015, cotton growers in the Dawson Valley had no access to localised, accurate weather forecasting tools and had to rely on information relayed from weather stations located in Biloela which is 116 km away. Thanks to the CRDC’s GrassRoots Grant program in 2015, three growers located in the Dawson Valley now have access to OzForecast services through the strategic placement of weather stations. These weather stations have significantly improved the decision making process of those cotton growers able to access them. However, the provision of timely and accurate data for some of the Valley highlighted the lack of this service in other geographic locations. Due to the topography of the Dawson Valley, the station located at Gibber Gunyah services the growers located on the Western side of the Dawson River but not the growers located on the Eastern side of the Theodore township. It was determined that one additional station, located strategically on the boundaries of three of the growers located on the Eastern side of Theodore would provide much- needed weather information to not only these three growers but an additional two located in the same precinct. Similarly, the weather station located at ‘Glendale’ provides excellent weather knowledge for the 1500 acres cotton planted in this locale but did not transcribe to the surrounding properties, located upstream.The assistance to fund an additional two weather stations has provided the Dawson Valley with excellent and complete coverage of the weather patterns and forecasts, greatly assisting in farm, crop and environment management decisions.

Over the three years of this project, data has been collected on the resistance status of silverleaf whitefly, Bemisia tabaci (MEAM1) to registered insecticides. In response to emerging resistance to the IGR pyriproxyfen, a recommendation to restrict usage of this IPM-compatible product to a 30 day window was adopted for the 2017/18 cotton season. This usage window has remained in place for subsequent seasons and testing indicates that resistance levels have stabilised. This research has been submitted for publication in Austral Entomology and is currently under review.

In 2016 resistance to spirotetramat was detected at two localities in North Queensland. Subsequent research has focused on understanding the underlying genetics of this resistance, and is in preparation for publication. In the most recent season (2018/19) resistance to spirotetramat was found in Emerald, which is the first record in a cotton production region. In response, the IRMS has been changed to restrict the usage of this insecticide to a single use per field (except for fields treated for mealybug which require a double application as per label direction to be effective).

Resistance to acetamiprid was suspected in the Macintyre region near Goondiwindi after the first round of bioassay testing. Further testing couldn’t confirm resistance, suggesting an initial false positive result.

Over the duration of the project, baseline susceptibility testing of products entering the cotton marketplace for control of silverleaf whitefly has been completed. This includes buprofezin, acetamiprid, emamectin benzoate and afidopyropen. A manuscript documenting earlier testing of products including spirotetramat, cyantraniliprole and dinotefuran was published in Austral Entomology.

In response to the widespread outbreaks of silverleaf whitefly, particularly in the 2016/17 season, the project team has actively engaged in extension events facilitated by the CCA and CottonInfo. This has included the production of videos on both resistance monitoring and whitefly parasitism.

Interest in assessing whitefly parasitism has grown steadily over the course of the project and knowledge on how to assess parasitism was presented at workshops run by the CCA at Moree, Dalby and Griffith. Evaluation of the toxicity of newer products against Eretmocerus was undertaken, but further experiments are needed to confirm results before this research can be confidently extended to industry.

The widespread extension of whitefly management issues, including stickiness, resistance and parasitism means cotton agronomists are better informed on the threat whitefly poses and the critical role IPM will play going forward.