Resistance is one of the greatest threats to effective pest control in the Australian Cotton Industry, both against insecticides as well as transgenic cotton. For the primary pests of cotton, the cotton bollwonn Helicove1pa armigera and to a lesser extent H. punctigera, this threat could in the worst case result in loss of an important insecticide or loss in effectiveness of one or more Bt genes. It is important therefore that resistance monitoring, and associated mechanism research, is continued to detect the development of resistance and determine the mechanisms involved, in order that appropriate strategies are formulated accounting for this information and implemented before resistance is observed in the field in the form of control failures.

The 2004/05 cotton season saw the introduction of large scale Bollgard II plantings with minor restrictions on the total area that could be grown. Insecticides however have continued to be in demand for use against Helico1·erpa spp. on conventional cotton, and have been used on Bollgard II crops either targeting other insects such as mirids, using a chemical that also kills Helicoverpa spp. (eg endosulfan), or to control Helicoverpa spp. under conditions of high insect pressure and/or growing conditions that adversely affect Bt expression. Sprayed conventional cotton (non Bt) is still a popular cropping option as well as an important refuge option for Bollgard IL While Bollgard II may dominate total plantings, conventional cotton plantings represent a significant area that requires insecticidal control and protection against insecticide resistance.

The effects of significant plantings of Bollgard II and planting trends for the future are uncertain for the foreseeable future given such factors as economic constraints (eg low cotton prices and increased Bollgard II fee) and resistance issues associated with Bt toxins. Findings of Dr Robin Gunning of NSW DP!, as part of the CRDC funded project DAN I 72C (Gunning et al., 2005) identified an esterase mediated cross resistance in H. armigera between pyrethroids and the Cry1 Ac gene, one of the Bt genes expressed in Bollgard IL In addition, while accurate estimates of the frequency of resistance to Cry2Ab, the other Bt gene in Bollgard II, continue to be established, the CSIRO Bt resistance monitoring project has identified resistance associated genes in the field, with the data suggesting an increase in frequency in 2007/08 (Sharon Downes, pers comm.). Both these findings have serious implications for the control of I-I armigera in the field using both conventional chemistry and transgenic cotton, and emphasise the need to continue insecticide resistance monitoring and associated resistance mechanism research, both An insecticide resistance management strategy (IRMS) is implemented in the Australian Cotton Industry to protect insecticides. This strategy relies on resistance monitoring data and mechanism research as part of assessing the success of the strategy as well as formulating changes to account for resistance development that may be detected, and for occtmenee of cross resistance between different insecticides. This project aims to provide such data and any additional useful data from the monitoring program in the development of an effective strategy and guidelines for minimising the development of insecticide resistance.

In addition to resistance monitoring and mechanism research for chemicals currently registered for use on cotton, it is essential that new chemistries entering the industry have accurate dose-response data measured prior to their introduction. This accumulation of the baseline response allows for measurement of future changes and the detection of resistance development. Without this baseline data there is no means with which to detect resistance development until it is too late and field control problems or failures occur.

Winter grown cotton in the west Kimberley (near Broome) has produced exceptionally high yields (>10 bales/ha) and premium quality fibre. Crops are irrigated daily, according to a formula based on &quote;crop factors&quote; and daily evaporation. However, the crop factors are estimates derived from other areas and may not represent efficient water use. Generally, crops near Broome have required 9 ML/ha applied water compared to about 6 ML/ha for similarly grown crops on drip irrigation at Katherine (NT). There is a clear need to accurately define the irrigation requirements of Bollgard II® cotton grown in a winter production system in the west Kimberley.

Diminishing water supply, changing weather patterns and pressure to enhance environmental flows are making it imperative to optimise water use efficiency (WUE) on cotton/grain farming systems. Growers are looking for better strategies to make the best use of limited water, but it is still not clear how to best use the available water at farm and field scale. This research project investigated the impact of management strategies to deal with limited water supplies on the yield and quality of irrigated cotton and wheat. The objectives were: (1) to develop irrigation management guidelines for the main irrigated crops on the Darling Downs for full- and deficitirrigation scenarios, taking into account the critical factors that affect irrigation decisions at the local level, (2) to quantify the evapotranspiration (ET) of Bollgard II cotton and wheat and its relationship to yield and quality under full- and deficit-irrigation scenarios, and (3) to increase industry awareness and education of farming systems practises for optimised economic water use efficiency.Objective (1) was addressed by (A) collaborating with ASPRU to develop the APSFarm model within APSIM to be able to perform multi-paddock simulations. APSFarm was then tested by conducting a case study at a farm near Dalby, and (B) conducting semi-structured interviews with individual farmers and crop consultants on the Darling Downs to document the strategies they are using to deal with limited water. Objective (2) was addressed by (A) building and installing 12 large (1 m x 1m x 1.5 m) weighing lysimeters to measure crop evapotranspiration. The lysimeters were installed at the Agri-Science Queensland research station at Kingsthorpe in November 2008, (B) conducting field experiments to measure crop evapotranspiration and crop development under four irrigation treatments, including dryland, deficit-irrigation, and full irrigation. Field experiments were conducted with cotton in 2007-08 and 2008-09, and with wheat in 2008 and 2009, and (C) collaborating with USQ on a PhD thesis to quantify the impact of crop stress on crop evapotranspiration and canopy temperature. Glasshouse experiments were conducted with wheat in 2008 and with cotton in 2008-09. Objective (3) was addressed by (A) conducting a field day at Kingsthorpe in 2009, which was attended by 80 participants, (B) presenting information in conferences in Australia and overseas, (D) presenting information at farmers meeting, (E) making presentations to crop consultants, and (F) preparing extension publications.As part of this project we contributed to the development of APSfarm, which has been successfully applied to evaluate the feasibility of practices at the whole-farm scale. From growers and crop consultants interviews we learned that there is a great variety of strategies, at different scales, that they are using to deal with limited water situation. These strategies will be summarised in the &quote;Limited Water Guidelines for the Darling Downs&quote; that we are currently preparing. As a result of this project, we now have a state-of-the-art lysimeter research facility (23 large weighing lysimeters) to be able to conduct replicated experiments to investigate daily water use of a variety of crops under different irrigation regimes and under different environments. Under this project, a series of field and glasshouse experiments were conducted with cotton and wheat, investigating aspects like: (A) quantification of daily and seasonal crop water use under nonstressed and stressed conditions, (B) impact of row configuration on crop water use, (C) impact of water stress on yield, evapotranspiration, crop vegetative and reproductive development, soil water extraction pattern, yield and yield quality. The information obtained from this project is now being used to develop web-based tools to help growers make planning and day-to-day irrigation decisions.

Final Report - Temperature time thresholds for irrigation scheduling in drip and deficit furrow irrigated cotton

Final Report - Hydrological and geophysical characterisation of palaeochannels in northern NSW

The adoption of Integrated Pest Management (IPM) principles plays a crucial role in the future sustainability of a cotton industry based on transgenic cultivars in the Northern Territory (NT).

Final Report for Cotton Catchment Communities Project 1.02.06 Honours Thesis A Method For The Simple And Rapid Determination Of Deep Drainage And Its Requirement

The Australian cotton industry depends heavily on genetically engineered Bt cotton (currently in the form of Bollgard II®) which provides resistance to the key pests of cotton, larvae of the moths Helicoverpa armigera and H. punctigera. Bt cotton has enabled substantial reductions in the use of insecticides, provided greater flexibility on cotton farming systems, and made the crop easier to grow. However, as with most pest management tactics, there is potential for the pests to develop resistance, and to counter this the Australian cotton industry has developed comprehensive Resistance Management Plans (RMPs), observance of which is mandatory for growers of Bt cotton. A traditional component of RMPs, dating from resistance management of conventional insecticides, is pupae busting, or cultivation of the soil to destroy overwintering (and potentially resistant) pupae. However, pupae busting incurs financial, agronomic and environmental costs. It restricts the implementation of minimum tillage techniques which can help prevent erosion, conserve soil moisture and enhance soil carbon. Moreover, we have demonstrated through modelling studies in this project that in modern Bt cotton systems, with high fruit retention and early maturation, many potentially resistant insects are emerging before overwintering diapause is initiated, and are thus not vulnerable to pupae busting. There is a need to develop tactics for RMPs that can fill this gap.One potential tactic is to target moths instead of pupae, using the attract-and-kill technology Magnet® which was developed by the researchers in this project during early work in successive Cotton CRCs. Magnet® consists of a mixture of plant volatile compounds which, when combined with small quantities of insecticide, can attract and kill adult Helicoverpa spp. moths. It has impacts beyond the area in which it is applied, but with careful placement it might be able to kill proportionately more potentially resistant moths from cotton than susceptible moths from refuge crops and other sources, thereby enhancing the genetic dilution effect provided by refuge crops which are another component of RMPs. A farm scale trial conducted during this project indicated the feasibility of this approach, and helped develop techniques to be used in a larger, area-wide trial of the approach to be conducted over the next three years. If successful, this trial could lead to the development of more robust RMPs, and the reduction of elimination of the requirement for pupae busting.

The Australian Cotton Comparative Analysis provides the industry benchmark for the economics of cotton growing in Australia. The report focuses on the economics of the 2015 crop from growers across the different cotton-growing valleys. It also presents trends that have been measured against more than ten years of data. The Cotton Comparative Analysis is a joint initiative of CRDC and Boyce Chartered Accountants.

Enhancing the Efficiency of Bt Refuge Crops within a Changing Cotton Environment