Many growers are unable to utilise new and transformative technologies due to their farm location not having access to a phone signal and or acceptable internet capabilities. Mobile black spots create limitations to productivity, profitability, sustainability, and safety of Australian cotton farms. As with the other regions of the world, the next biggest movements in productivity and growth for future generations will come from technological advancement. The level of Agtech development occurring throughout Australia is quite impressive; however, there is one considerable barrier to entry for many producers: the infrastructure connecting these devices to the internet.
The risk to the Australian agriculture industry is our lack of internet connectivity in rural regions, which restricts our ability to adopt the latest technological developments.
 

DNA is a reliable indicator of background disease inoculum levels. The value of that background diseaseinoculumisthenareliableindicatorofspatialdiseaseriskandsubsequentcropyieldsolongas other crop production variables are eliminated or accounted for such as:

• The pathogenic virulence of the strain of Verticillium
• Fusarium
• Plant population and uniformity.
• Irrigation management
• Nutrient availability and distribution – spatially and at depth
• Compaction
• Weather conditions

The cotton industry needs access to a diagnostic test for Fusarium oxysporum (F.ov). Fusarium is the dominant pathogen in southern Queensland and parts of the Macintyre and Gwydir Valleys. Not knowing the levels of F.ov thwarts the accuracy and scientific benefit of the Vert/BRR test in those valleys. This should be an imperative for future funding and research.

Inoculum maps are already being used to assist:

• Target trial locations onto sites with known levels of background disease:
• CSD to improve the site location of their V Rank and disease management trials.
• CSD to assess the impact of certain Xtend Flex varieties have on resultant inoculum.

• Chemical companies targeting low, medium or high levels of disease inoculum for efficacy trials.
• Chemical companies testing products for efficacy can now also add the treatments impact on resultant inoculum.
• Source sites with either Defoliating or Non Defoliating dominance.
• Monitor the impact of alternative crops on disease inoculum levels. CAS are the primary service provider for monitoring disease levels as part of the Richard Williams Disease Initiative to identify crop management practices that can assist with on-farm disease management. It is a grower participatory project to encourage growers and consultants to assess the value and cost of alternative practices across different farming systems and environments.

It is premature to make any recommendations on the predictive Yield Loss Risk as determined by DNA inoculum levels for BRR and Verticillium. Further research, taking into account the strain of Verticillium, is required for any yield loss thresholds to be set. Having said that, it does enable prioritisation of fields, to be planted to cotton, based on inoculum population densities and spatial distribution.

Cotton consultants now have these DNA diagnostics as a reliable tool for the detection, measurement and management of cotton disease on behalf of their clients. Consultants have the responsibility of protecting their clients crops from biotic threats, of which disease is often the most damaging. Disease management takes a long term and integrated approach. No longer should the grower be solely responsible for crop sequencing and field preparation, consultants need to be actively involved to in crop management earlier during the preceding years and during the fallow period. Consultants can use these disease inoculum measurements, to run their own trials and case studies.

• to establish their own field thresholds,
• assess the efficacy of specific agronomic practices such as crop rotations, N management, irrigation management and
• assess any yield impact of crop products and/or the impact of resultant inoculum levels.

Over time, by taking many more data points and with the advent of Interpretive Machine Learning, these and other data sets will provide the basis for establishing not only the direct interactions of Inoculum x Disease x Yield, but also their responses to specific weather conditions. For example, for a particular field with known inoculum levels, physical and chemical soil properties and elevation…what will the yield outcome be in a Decile 2 rainfall (hot and dry) year v a Decile 9 rainfall year (wet and cool). This could be further refined into specific weather Deciles for rainfall and temperature during specific crop stages (Day Degrees) x Month. Intuitively then and ultimately, yield loss estimates could be used relative to known objective measurements and according to a long range weather forecast. Similar retrospective findings could be associated with the confirmation of the virulence of the strain of Verticillium for each field.

I (Dr Karen Kirkby) received an invitation from Dr Jason Woodward from Texas Tech University and Dr Terry Wheeler from Texas A&M AgriLife Research & Extension Center at Lubbock to visit the laboratories at the Lubbock Center and visit production fields throughout the High Plains as well as to learn their isolation techniques used to quantify Verticillium dahliae from soil following the APS Meeting in San Antonio. This travel would allow Dr Kirkby to attend and present (should her abstract be selected), the APS Annual Meeting in San Antonio from the 5th-9th August followed by a two week visit in Lubbock between 10th and 26th August, 2017. 

The meeting titled Changing landscapes of Plant Pathology will hold field trips, APS Connects – Networking events as well as workshops. The workshop titled Morphological ID of phytopathogenic fungi held on Saturday 5th 9am – 4pm is particularly relevant along with the special session on the re-emergence of bacterial blight. 

My abstract submission titled “Genetic and morphological characterisation of Verticillium dahliae collected from cotton crops throughout NSW, Australia” has been submitted. Presenting this research to an international audience will be used to demonstrate the difference characteristics of Australian Verticillium dahliae isolates in comparison to those published in literature to date.  It will also outline the successful international collaboration between NSW DPI and Spanish collaborators.  Attending the workshop titled “Morphological ID of Phytopathogenic fungi” will provide the opportunity increase diagnostic skills and learn techniques used to identify pathogens of interest using morphological characteristics. 

Extending the trip to include a two week visit with Dr Jason Woodward and Dr Terry Wheeler will have direct benefits to my current research project “Managing Verticillium risk for Cotton”.  Both Jason and Terry developed the risk matrix for Verticillium and inoculum levels currently used in the USA.  The opportunity to work with these researchers will enhance my understanding and skills surrounding the development of a similar risk matrix for Australian cotton industry and these relationships will remain invaluable progressing forward.

CRDC and NSW DPI investment in cotton pathology research capacity at ACRI has increased since 2016-17 with the initiation of three new pathology research projects and the appointment of Dr Duy Le and Ms Aphrika Gregson. 

During a review of cotton pathology research infrastructure NSW DPI and CSIRO identified significant deficiencies in autoclaving capacity at the Australian Cotton Research Institute – Narrabri. 

Access to autoclaving technology is essential for many NSW DPI and CSIRO research programs based at ACRI as the current unit performs cleaning and decontamination of laboratory glassware, media and waste. After careful consideration NSWDPI and CSIRO agreed to approach CRDC to secure industry funding to procure an additional 100 litre autoclave unit.

Additional autoclave capacity will support the analysis of key pathology issues and identification of potential solutions for disease control leading to delivery of improved integrated disease management strategies for cottongrowers.

The Australian cotton industry has made considerable yield gains by improving genetics and agronomic management, which is ultimately limited by the environmental constraints in our growing regions. One of the major factors limiting yield in Southern NSW is the unpredictably cool start to the cotton growing season. This has a negative impact on grower’s ability to establish a consistent plant stand within an optimum planting window that allows sufficient length of season to obtain high yields.

Germinating cotton seed is an interaction between soil temperature, moisture and seed/soil contact. Depending on the season most growers are able to achieve a uniform, consolidated seed bed for optimum seed/soil contact but must react to fluctuating temperatures and consider irrigation water temperature at the time of planting. 

The results from this project suggest there is no silver bullet to improve yields. The attempts to improve crop establishment and increase early season growth returned nil significance during the seasons they were tested. The main outcome present across all experiments was that other agronomic management such as soil health, pest and disease pressure and seasonal environmental challenges limited the yield more than treatments imposed to affect establishment. 

Application of plant hormones to increase early season growth and boll loads have returned mixed results from work conducted in Australia and internationally. Irrigation and nutrition management play a large role in the efficacy of such products having an influence on yield components. For example, where soil conditions resulted in the crop experiencing potassium deficiency late in the season and undergoing early senescence, a review of the treatment effects of the products used is required. This work needs further investigation targeting compensatory growth and stress alleviation.   

Technologies such as biodegradable plastic applied over the seed line show promise to improve establishment but is highly dependent on planting date. Early planted crops experience an increased response to temperature/moisture dynamics when compared to late planted crops. The exercise of applying this plastic is expensive and requires a yield increase of 1 bale/ha in order for it to be worthwhile. Therefore, yield gains expected from application of the plastic should be done so on fields where there is no expected yield constraints from other factors such as disease or nutrition. 

Evaluation of factors limiting yield potential should be considered from a whole farm perspective and not just one facet of crop agronomy. While achieving a consistent plant stand is crucial to achieving high yields; other factors like nutrition, irrigation management, pest and disease control and seasonal conditions have a considerable influence on yield. Tackling all of this to improve yield is a massive task but over time with the skill set of the Australian cotton industry it can be done. 

The Australian cotton industry is a global leader in water use efficiency. As irrigation water continues to become an ever-more-scarce resource, the industry is increasing its commitments to continuous improvement in water productivity and demonstrating its responsible use of the shared water resource. 

This five year research and development project focused on improving on-farm water management and boosting productivity through the efficient use of water resources. This has been achieved through primary activities that included (1) the development of the weather based technology IrriSAT to guide irrigation scheduling, (2) the provision of a technical specialist to lead and coordinate industry wide water use efficiency campaigns and (3) benchmarking water productivity across the Australian industry and identifying long term trends in water productivity over the last three decades. 

The refinement and promotion of the IrriSAT technology to guide irrigation water scheduling has resulted in excess of 1500 growers and consultants becoming registered users. This has been achieved as a result of a range of promotional activities including webinars, workshops and field days. Commercial industry service providers have also taken up the use of IrriSAT, with Goanna Telemetry now having fully integrated the IrriSAT approach into their GoSAT web interface, integrating soil moisture probes and IrriSAT data into a combined irrigation management package for growers. 

To support and coordinate the improvement of irrigation management and water productivity in the cotton industry, three officers have provided Technical Specialist input to the CottonInfo team – Janelle Montgomery, Ali Chaffey and Ben Crawley. These officers have been incorporated in the CottonInfo team and have led a wide range of activities. These activities have included, the Irrigation and Nitrogen tours, which brought together researchers, advisors and growers to raise awareness of industry funded research programs and promote best practice, engaging with 519 participants across seven locations in eastern Australia. More recently, the Technical Specialist, in partnership with the CottonInfo team, has coordinated two major field days where approximately 220 growers and advisors were directly exposed to the latest technologies using siphon-less irrigation methods. Participants provided clear feedback that they had gained knowledge which would result in them making informed decisions regarding adoption of more efficient and water productive irrigation practices.  The field days have resulted in YouTube videos and detailed information booklets which are now being accessed by growers across the industry.

Benchmarking of water productivity has shown that growers continue to produce more cotton from less water – improving their status as the most water efficient producers in the world. Long term trends in rainfall and irrigation inputs have declined over time, but increasingly higher yields are still being produced. This has meant water productivity has increased at a rate of around ¼ bale more cotton per decade from each ML of total water, and roughly 1/3 more cotton per decade for each ML of irrigation water. Water productivity has improved from 1.12 bales per megalitre in 2012/13 to 1.20 bales per megalitre in 2017/18. Cotton growers are improving their management of irrigation water, for example by reducing losses to evaporation and seepage during transmission and storage losses. A comprehensive study of long term trends in irrigated cotton water productivity has been completed and its results are nearing publication in the scientific literature.

This research is helping to quantify and demonstrate that cotton growers are improving the productivity from every drop of water available, and this provides a platform for the industry to demonstrate and communicate its high level of stewardship of a crucial natural resource that needs to be shared – water.

Additionally, more efficient techniques have been developed under this project to monitor water productivity. An interactive dashboard has been developed which allows all growers participating in benchmarking, and their advisors, to track their level of water productivity, and more importantly to compare it with their peers, regionally and nationally. Further research is now taking place under a new project that will apply these new techniques to more closely identify the trends and drivers of water productivity, on an annual basis in both irrigated and dryland Australian cotton.

If cotton is the crop of choice in many irrigated systems it is because the industry has made great gains in water productivity and cotton is the most profitability use of the limited water available to growers.

For further information please contact 

david.perovic@dpi.nsw.gov.au or ben.crawley@dpi.nsw.gov.au

The NSW Government through its $50.8M World Class Food & Fibre 2 program allocated $5.7M to the upgrade of soil and plant research infrastructure at the Australian Cotton Research Institute (ACRI) based at Narrabri to meet the current and future research capability requirement to underpin food and fibre production in NSW. The project involved the construction and installation of equipment to support the operation of a new Plant Propagation facility and a new Soil and Plant Processing facility. These new facilities will support research into key research areas for the industry in agronomy, entomology, pathology, nutrition and soils.

CRDC provided a capital contribution of $475,000 to the ACRI program to facilitate the purchase of critical research equipment for the new facilities including:

- Growth Cabinet - Steridum PLEDT-RH500

- Leaf Area Machine - Licor LI-3100C

- Incubator - Steridum i170 

- Soil Oven - ODH50 

- Bioline Growth Room BDW80, and

- Laboratory Water Purification System, and

- 160KVA Diesel Generator

The equipment has been installed and is being used by research teams in the delivery of current CRDC funded research projects.

The Grains Research & Development Corporations (GRDC) also contributed an allocation of capital funds ($786,216) to the establishment of the 2 new facilities at ACRI. GRDC acknowledged that many cotton growers are also grain growers and that grain production is component of the cotton farming system.

The Supporting Southern Cotton Production project (DAN2001) was established in 2019 to research production issues identified from the agronomic information in grower surveys conducted by a previous project (DAN1701) over the 2016 and 2017 seasons. The survey found that cotton establishment and replanting remained the most difficult management challenges in the Southern 
valleys, with 30% seedling mortality and replanting outside the 2-week planting window resulting in a yield loss of 1–2 bales/ha. Other major influencing factors around these challenges included soil temperature, hot and cold shocks, seed depth at planting, irrigation water temperature and soilborne diseases in back-to-back cotton.
Operating alongside the Supporting Southern Cotton Production project was the Southern Cotton Crop Protection project (DAN1903). It was established in 2018 to address the crop protection issues faced by southern cotton growers and provide disease and invertebrate pest research and development expertise to the expanding Southern cotton industry. Real and perceived disease and insect threats to Southern grown cotton identified at the time included its relatively short production window, a high proportion of back-to-back or short rotations with cotton, a lack of southern specific management guidelines, and strong drivers towards continued high pesticide use with new growers being unfamiliar with cotton physiology and many relatively inexperienced 
consultants, primarily working for resellers, making crop protection recommendations, The two projects were merged in 2020 under DAN2001. All milestones for both projects were retained.

Jon Baird was appointed in the role of the lead researcher CottonInfo Tech Lead – nutrition.

During the project, Jon developed new research extension materials and collaborations within

the cotton industry to further improve grower’s knowledge and nutrition management

practices. Within the project there was a major revision to the annually produced Australian

Cotton Production Manual – nutrition chapter. The ACPM is a cornerstone for the industry and

delivers a standard for best management practices for Australian cotton growers and industry

personnel. The revision was based on recent data detailing N fertiliser losses in field tailwater

and quantification of N fertiliser movement within the soil profile. In addition, the project

developed specific nutrition management guidelines outlined for dryland cotton systems. The

guidelines gave growers a detailed management strategy similar to what is available for

growers using irrigation water.

As reported in other documents and reports many Australian cotton growers are applying

fertiliser N higher than what is required by the planted crop (industry fNUE was ~10 kg lint/kg

N compared to research optimum range of 13-15 kg lint/kg N). Therefore, a concise effort

was made to better understand the tools and strategies growers and agronomists use to

perform nutrition budgets. Through organised regional face-to-face surveys and nutrition

forums the project evaluated the industry’s thoughts on nutrition management and key goals

and processes which can reduce fertiliser loss and the production of gaseous emissions and

reduce the industry carbon footprint.

Survey results indicate 89% of growers use a nutrient budgeting tool, but the tool was not

the traditional industry developed tool – NutritLogic – but rather individual excel sheet

containing known formulas and factors. Also, growers were willing to utilise enhanced efficient

fertilisers (EEF) and were in favour of fertilisers that have a potential for lower carbon

emissions.

To generate greater industry knowledge and understating of nutrition, the project established

on-farm experiments to investigate N mineralisation utilising the CSD FastStart weather

stations network and an EEF study in the Southern valley. Mineral N dynamics across all the

Australian cotton valleys were monitored throughout the growing season. Research results

indicated application timing affected available mineral N, with pre-plant timing losing mineral

N from the 1st irrigation down to maturity, while in-crop application gave crops a spike of

mineral N during the mid-season months of December/January.

During the project, there was a noticeable drop in the application rate of fertiliser N from

2017/18 to 2020/21 (336 kg N/ha and 253 kg N/ha respectively). The decrease in application

rate had a positive influence on irrigated cotton fNUE (14 kg lint/kg N) which was the first

recorded industry fNUE in the optimum range of 13-18 kg lint/kg N in the last ten years of

CRDC grower survey data. While factors such as smaller production area and higher mineral

N from fields in long fallows may have contributed to the fall in application rate, there has

been a conscious shift in grower attitude to improve their management on nutrition especially

as economic impacts such as low turnout and poor fibre quality are highlighting implications

of excessive N fertiliser use.

Verticillium wilt caused by the soilborne fungus Verticillium dahliae, is one of the most challenging and economically significant diseases of cotton in Australia and worldwide. Host resistance is regarded as the most effective control strategy, however the biological complexity of the pathogen and controversy regarding the mechanisms of resistance hinder plant breeding efforts. Previous studies have utilised GFP-tagged isolates of V. dahliae to investigate the host – pathogen interaction on cotton, providing insights into the host resistance response and little understood areas of the disease cycle. Here, we establish GFP-tagged isolate Vd71-3 as a tool for evaluating infection and colonization on cotton cultivars tolerant and susceptible to Verticillium wilt. Isolate Vd71-3 was obtained by transforming a GFP vector construct into highly virulent non-defoliating strain Vd71171 isolated from a diseased Upland cotton plant in NSW, Australia. Prior to study on cotton, pathogenicity of Vd71-3 was deemed consistent with that of the parent wildtype, indicating that GFP expression does not dramatically alter virulence. Confocal laser scanning microscopy observations confirmed existing descriptions of early infection on cotton, including germination of conidia by 24 hours post-inoculation, formation of an infection peg, intercellular colonisation of the root tips but not lateral root junctions, preferential colonisation of the xylem vessels, and acropetal movement of conidia in vessels. Extensive fungal occlusion of the vessels was also observed, not previously captured elsewhere on cotton.

V. dahliae was recovered from six of the eight weed species that were inoculated with the transformed VCG 1A and 2A strains. The VCG 2A transformant was recovered more frequently from weeds than the VCG 1A transformant, suggesting that V. dahliae VCG 2A may have higher infectivity towards weed hosts in Australian cotton fields. V. dahliae was not recovered from seeds from cotton plants that were subject to direct stem inoculation, although vascular tissue adjacent to the site of inoculation was colonised. Further investigation is needed to understand whether V. dahliae VCG 1A and 2A strains are capable of infecting Australian cotton seed using alternative inoculation techniques.