The process of improving on farm energy use includes an energy assessment which benchmarks and establishes energy saving opportunities. The concept involves 3 types / levels of assessment. The energy user may decide on any level of audit or start with a Level 1 audit and use these results to inform further progression.

This brief provides summary data for the Cotton Research and Development Corporation to report on progress in relation to sentinel work health and safety indicators.

While the industry appears to be making progress there are several limitations to this study and the data within, that need to be considered. Firstly, accurate denominator data to ascertain rates of injury and death are not available and have not been presented in this report. This is particularly important as the impact of the extended drought and reduction in water allocations on the cotton cropping area planted is likely significant. This has implications in terms of both the volume of work undertaken and indeed the number of people working within the commodity sector. Without question, this reduces the overall exposure of workers to potential risks and may be partly reflected in the lower number of weeks lost in the last two years of this study period.

This project funded the purchase of four row cotton precision planter for the establishment of cotton experiments in southern NSW.

As the cotton industry rapidly expands into southern NSW, the purchase of a four row cotton precision planter significantly enhanced the ability of NSW DPI Plant Systems Branch and other research organisations to deliver accurate results from existing cotton research projects in the southern connected systems. This capital investment project significantly reduces the risk of poor establishment of cotton trials by providing control over plant density, plant spacing and seed placement relative to the soil surface. The four row planter will also mean easier movement of the equipment between the research stations Yanco Agricultural Institute and Leeton Field Station.

CRDC and NSW DPI have co-invested in the purchase of this four row precision planter which will run on the bed surface, eliminating variable plant establishment issues in seed spacing and placement that have occurred through the use of other equipment.

Adapting to extreme weather events under current and future climate conditions will be necessary to maintain industry profitability and sustainability. To develop strategies to adapt and assist recovery from these extreme climate events, a robust adaptation knowledge framework must be developed within the context of climate change scenarios. The objectives of this project was to examine the impact of extreme events (flooding and drought) under current and future climate (elevated CO2 and temperature) on soil fertility and function; and how these changes in soil processes affect cotton productivity through better understanding of soil-plant interaction and environmental sustainability.

Climate change impacts

• TE was the dominant factor in cotton productivity, accelerating the rate of plant development and vegetative growth while elevated CO2 (CE) had a strong impact on leaf physiology.

• Vegetative growth was dominated by the interactive effects of elevated temperature (TE) and CE on phenology, physiology and soil nutrients, and crop responses were similar in the two soils.

• However, during reproductive growth, the effects of TE and CE were limited by soil N availability, inducing changes in resource allocation between vegetative and reproductive growth.

• Such positive responses observed in the first season disappeared in the second season, as cotton productivity was influenced by legacies of CE and TE on soil and microbial properties.

• In particular, the legacy of CE effect through crop residue on soil and microbial properties strongly reduced soil N availability, altering resource allocation more towards belowground and less towards seed cotton yield.

• CE and TE also altered the abundance and composition of soil bacterial community, which showed strong correlations with soil chemical properties and soil processes, suggesting that shifts in soil microbial community could impact crop productivity through changes in nutrient cycling and availability.

Implications for Growers

• More N fertiliser will be required to prevent N limitation at CE for crop production under future climate.

• The responses of soil nutrients and microbial community should be an integral part of climate adaptation strategies.

• The response of non-harvestable biomass to these environmental changes should also be considered and implemented as a part of residue management strategies.

Extreme weather impacts

• The magnitude of flooding and drought impact on cotton productivity was greater at future CO2 and temperature regimes, suggesting that inter-annual variability in yield is likely to increase under more extreme climates.

• We also found that flooding and drought had contrasting consequences for soil N availability, with drought-induced loss of biological activity resulting in a large amount of residual N in the soil.

• Flooding and drought events occurred in the previous season can affect the soil and microbial properties and that those changes can indirectly influence cotton productivity of the subsequent season.

• In particular, changes in the abundance of nitrifier communities were strongly linked to soil processes that provide plant available N.

Implications for Growers

• Differential fertiliser management strategies are needed to minimise the legacy impact of extreme weather events. Our results suggest that more N fertiliser will be needed to ensure the productivity of subsequent crop following a flooding event, while the opposite is needed following a prolonged drought event.

• Soil microbial communities play an important role in minimising impact of climate change and extreme weather events on cotton productivity. Thus, the management practice which promotes soil health and microbes should be adopted for improved and sustainable cotton production.

Verticillium wilt of cotton is caused by Verticillium dahliae, a soil borne fungus that enters the roots and grows into the vascular system of the plant. Identifying Verticillium is the first step in being able to manage it.

This two-year trial aimed to explore soft management options for whitefly management in the southern valleys. The drivers of this were, managing the risks associated with sticky cotton and the wider industry impacts that were occurring to neighbouring industries such as horticulture. The first year of the trial focused on the use of oils and detergents as a means of control in a small plot, replicated trial at the Irrigation Research Extension Committee Farm, coupled with sticky trap monitoring and a small area of parastoid wasps, Eretmocerus hayati, released. The results from the first year found that there was no benefit from the use of sticky traps in terms of trying to detect a whitefly population earlier. There was also no significant difference between the detergent and oil treatments.

Second year trial looking at the best soft management options after consultation with the wider growing community in the Whitton region, the project direction was changed to broadscale management of whitefly through a combination of soft pesticide applications, oils and the release of Eretmocerus hayati across a wide area to try and influence populations. Sticky traps where used again to try and detect populations earlier. Once again, the sticky traps proved to be of no benefit in the early detection of whitefly. Higher levels of parasitism were achieved where releases were made as expected but from the data collected it was possible to see that the release of the whitefly parasitoids resulted in higher levels of parasite nymphs and a lower whitefly population by the end of the period. It was also possible to see that other fields on the farm where parasites were released, but not directly released on had spikes in the parasitism levels as well as reduced overall whitefly nymph numbers, consistent with the fields that had the releases. The data collected, shows that there was some success in the use of parasitiods for helping reduce the numbers of viable nymphs. Some of the challenges that we will continue to face going forward, are the need to commit to using the wasps at the start of the season when there is no way of knowing what the end of season pressure will be like, and the issues around getting the wasps due to northern demand. There was also an issue with some growers opting to spray fields early rather than allow the parasitised field run their course so we had to remove some data. Overall, the practice change of heading towards the use of beneficials from this work appears viable and this provides some confidence to the growers that they can offer some level of control.

This travel funding sponsored attendance at the intital planning meeting for the Rural R&D for Profit project “Improving Plant Pest Management through Cross Industry Deployment of Smart Sensor, Diagnostics and Forecasting”.

The introduction of insecticidal transgenic varieties into the Australian cotton market in the mid-1990’s allowed the industry to substantially reduce its pesticide use but resistance continues to threaten its efficacy. Indeed, CSIRO has isolated resistance in the key targets H. armigera and H. punctigera to all three toxins (Cry1Ac, Cry2Ab, Vip3A) in the current Bollgard 3 varieties. This is set in the context of an emerging global pesticide crisis that could see novel resistant variants of these pests selected elsewhere arrive into Australia.

The industry relies on a pre-emptive strategy to slow the development of Bt resistance. This is underpinned by independent monitoring of background resistance frequencies to enable the industry to autonomously respond to emerging issues, as well as research on other high priority stewardship issues related to Bt resistance in Helicoverpa species. The project was conducted in the following three parts.

PART 1: Does multiple resistance to Bt toxins in Helicoverpa spp. pose a threat to 3 gene cotton?

There is a high chance of an insect being resistant to Cry2Ab and Vip3A. Cry1Ac declines as plants age which creates selection opportunities. Our laboratory bioassays demonstrated that it is possible to select for Cry1Ac resistance in a Cry2Ab / Vip3A background.

Experiments with multi-resistant colonies (created from resistant field colonies) challenged with field grown 3-toxin cotton suggest that they carry a fitness cost but can nevertheless survive well from the neonate to 3rd instar stage. As the larvae mature they are likely to die on 3-toxin cotton but a small proportion can survive.

PART 2: Are the frequencies of resistance to 3 gene cotton increasing?

During 2017/18, we used F1 screens to sample populations of H. armigera and H. punctigera throughout the industry and did not find evidence of increases over time in the frequencies of resistance to Cry1Ac, Cry2Ab and Vip3A. We also performed F2 screens and did not isolate any dominant forms of Bt resistance but we did isolate a new recessive Vip3A resistance in H. armigera. Our continued survey of CCA members since 2008 supports frequency estimates which suggest that Bt resistance in Helicoverpa species is not increasing.

To assist with development of the molecular tool (as part of CSE1801) we examined F2 and F1 individuals previously identified as resistant using bioassays during our monitoring program. We: (1) screened for previously identified mutations and (2) examined whole genome data for novel mutations.

PART 3: What are the characteristics of different variants of Cry2Ab resistance?

There is no indication from our characterisation work that a novel variant of Cry2Ab resistant H. armigera poses a different threat to that of the first isolated variant.

Summary: It is unclear to what degree multiple resistance to Bt toxins in Helicoverpa spp. is a threat to stacked gene cotton. Our data suggest that currently there is no reason to consider changes to the Resistance Management Plan for Bollgard 3 cotton. However, it will be important to get a more complete understanding of the characteristics of the various isolated Vip3A resistance colonies to inform future methods / tools for monitoring resistance. It is also essential to validate the molecular tools being developed with standard bioassays to translate and incorporate them into future monitoring programs. Although there currently is no evidence of increasing resistance, it is critical to pre-emptively ascertain any future changes due to, for example, incursions of novel resistances from overseas and/or changing climates driving local selection in Helicoverpa and/or other pests that may carry novel resistance genes to key technologies used in Australia (i.e., Fall Armyworm).