The Australian Cotton CRC extension team conducted the second cotton industry benchmarking study during the 2000/01 season. It was implemented as a follow up to the 1997 survey that focussed on the 1996/97 season to measure changes in industry practice during the four-year period and to identify current issues for research, development and extension. This paper provides a broad overview of the survey results. The extension team focus groups will be undertaking detailed analyses of data with respect to specific aspects including agronomy and fanning systems and the management of weeds, water, insects, diseases and spray application. The information derived from the data is of substantial value when used in the identification, prioritisation and planning of research, development and extension programs.

There is speculation that current secondary pests of cotton may be more troublesome following the introduction of transgenic cotton. There is concern that increased sprays targeted at the secondary pests, such as cotton aphid, may exacerbate resistance. To quantity resistance in cotton aphid eleven strains were collected from Qld, NSW, NT and WA and tested. Carbamate and organophosphate resistance was detected in strains from Qld, NT and WA but not NSW. Profenofos resistance was low (max. 4.7x), omethoate resistance high (max. 42.1x) and pinnxicarb resistance extreme (max. 1,736x). Low level endosulfan (max. 1.4x), and pyrethroid resistance (max. 4.1x esfenvalerate) was detected in one NSW strain. The implications of the findings of this continuing study are discussed.

Historically, the wild Australian Gossypium species have played a minor role in cotton breeding. Before 1980, this was mostly due to the rarity of material in germplasm collections, which contained only the commonest species (e.g., G. australe & G. sturtianum). A series of collecting expeditions in the 1980s addressed this situation, and the CSIRO Gossypium germplasm collection now contains accessions of every known species. This presents the opportunity to use all the Gossypium species that evolved in Australia to develop better Australian cotton cultivars. This article summarises ongoing work to develop strategies to overcome the extensive crossing barriers that preclude exchange of genetic material between the wild Australian Gossypium species and the cultivated cottons in nature.

Sustainability in any farming system is dependent upon a number of interacting factors which include climate, soil quality, plant nutrition, management, weed and disease incidence, and economic factors (Greenland and Szabolcs, 1994). Measures of soil quality in agricultural land include soil tilth (described by porosity, aggregation and other structural measures) as an index of soil physical quality, and pH, N, exchangeable cations, salinity, toxic chemicals and soil organic carbon as indicators of soil chemical quality (Karlen et al , 1992; Walker and Reuter, 1996). Among these, soil organic carbon has been proposed as a primary indicator of soil quality (Lal, 1997; Reeves, 1997). The frequency and amounts of carbon and N inputs needed to replenish soil carbon and N reserves have been suggested as good indicators of long-term sustainability of many cropping systems, and has been incorporated into predictive models of sustainability (Fig. I) (Lal, 1997; Reeves, 1997; Freebairn et al, 1998). Predictive models derived for dryland clay soils suggest that the first indicators of a system run-down under commercial cropping are increased requirements of fertilizer N (and other nutrients such as P and S) and water to maintain yields. In the longer-term yield and profitability losses also occur (Freebairn et al, 1998).

Polymeria longjfolia (Polymeria take-all or Peak Downs curse)is a native Australian species. It is one of the 'take-all' weeds, so named because of the 'perennial, rhizomatous habit' of many of these weeds, their ability to form 'dense competitive infestations that smother the ground' and that they 'take all 'the nutrient and water resources available in the soil (Sindel pers. coimm. ). It has long narrow grey/green leaves with pink/mauve, yellow-centred flowers. It forms a dense rhizomatous root system which appears to be largely resistant to chemical and cultivation treatment (McMillan 1988). Polymeria take-all was ranked as the tenth worst weed in New South Wales cotton growing areas in the 1988/89 season (Charles 1991). It appeared to be increasing in abundance at this time. Control measures for Polymeria take-all were far from satisfactory and progress towards such measures had been slow due to a lack of research effort (McMillan 1988). Our research aimed to survey the distribution, spread and potential for control of Polymeria take-all, and to elucidate the reasons for the success of this weed by examining aspects of its biology and ecology in the cotton fanning system.

Distributed across every major cotton growing region, the Australian Cotton CRCs National Extension Network aims to enhance the returns to industry accruing from the implementation of research and development. Industry Development Officers (IDO), District Agronomists, specialist officers in the areas of Water Use Efficiency, Irrigation, integrated Pest Management (IPM) and Spray Application Technology and a National Coordinator provide a close link between industry and research. In addition to their local role, each member contributes to a national extension effort through one of the Insects, Farming Systems, Environment, Diseases SE Weeds or Water focus teams. These teams work closely with researchers and their ACGRA members to ensure that consistent messages are extended across the industry with minimal duplication of effort.

Cotton is one crop with an opportunity for a true integrated weed management strategy to be implemented. New herbicide chemistry, genetic engineering and new machinery when combined together offer the prospects of achieving a more environmental and ecologically sustainable weed management approach for the industry. This paper aims to briefly discuss three weed management issues for the cotton industry. Firstly, examining current weed management systems in the cotton industry, high-lighting some of the advantages and potential problems associated with current management strategies. Secondly, addressing weed management techniques that are likely to be adopted in the future and thirdly a discussion on the future of using manual 'chipping' in the industry.

Bacterial stunt is a disease in which soil borne bacteria colonise cotton roots and inhibit the growth and mycorrhizal development of the plant. Brown discolouration develops rapidly in the roots of stunted plants. Stunting is relatively uniform and, therefore, may only be noticeable when parts of a field are affected and parts not. Stunting tends to be more severe in heavy clay soils, even though these soils may have high levels of nutrients such as phosphorus (Nehl et al 1996a, 1996b). In some cases crop growth picks up mid-season and yields are acceptable but yield loss of up to 50% occur when cotton is severely affected. There are few options for control of bacterial stunt. Eradication of the pathogenic bacteria from soil is impractical. Permanent bed systems appear to have lifted yields, although the relative patterns of stunting across fields remain. At present the best option for control is to optimise management of the crop

Cotton aphid and two-spotted mite have the potential to cause dramatic reductions in the yield and fibre quality of cotton. Management of these pests is strongly dependent on insecticides and acaricides. Recent development of resistant in both species now threatens the sustainability of their control. This project will monitor resistance in mites and aphids to existing control options, and establish baseline resistance and cross resistance data for new chemistry. This will enable continued development of effective resistance management strategies and integration of new control options, thereby maintaining the sustainability of cotton production. This will be best achieved by pursuing an integrated approach, including monitoring, cross-resistance testing, mechanism elucidation, and the evaluation and the timely inclusion of new chemistry that is compatible with IPM. This project will monitor the resistance of mites and aphids to a wide range of current control options. For new options, biological and synthetic, a sound knowledge of the base-line (initial) resistance levels and cross resistance profiles will be developed so they can be effectively incorporated into resistance management strategies. Without this study Australia's capacity to manage these pests, and in particular our reputation as a producer of clean lint, uncontaminated with aphid honeydew, could be dramatically affected.

In recent times there has been general recognition that broad based legislation, while it must remain the cornerstone of community standards, does not fully address the needs of the community for better environmental performance. Laws can only enforce to a standard, they do not encourage performance greater than the standard. This has led to various sectors of the community putting in place Quality Assurance or Best management or Codes of Practice programs for the dual purpose of encouraging members of their sector to improve their performance above the law to a common benchmark for internal reasons and to provide a vehicle to demonstrate to other sectors of the community that they are responsive to, and share, the general increased awareness and concern with respect to environmental performance.