The efficacy of Bt cotton plants against field populations of Hencove, :po grinigero has not been consistent over the growing season. A repeatable late-season reduction in efficacy has been observed and variation in efficacy has also been recorded early in the season (Fitt at o1.1998). The early season problems are particularly worrying because the cause is unclear, although hypotheses abound.

The variation in efficacy observed could reflect changes at the level of the genome. The

unexpected inactivation of transgenes leading to the loss of a newly introduced trait has been well documented (reviewed in Stain eta1. , 1997). Transgene silencing in response to environmental stresses, such as high light intensity or elevated temperatures, has been reported both for plants growing in the field and in experimental plants growing in controlled environments (Meyer erg1. , 1992; Walter eta!., 1992). An understanding of the molecular basis for both the developmental(late season) and early season decline in efficacy of Bttransgenic cotton will provide a basis form alding decisions concerning the management of the current Bt cotton lines and the development of new lines with insertions of the Bt transgene.

On 21st November, at Narrabri, over forty Workshop participants,

mostly ginners, developed and discussed the following introductory

Best Management Practice for the Australian Cotton Ginning

Industry. The Workshop supported the scope and format proposed

by the Australian Cotton Ginners Association (ACGA). This involved

the setting of "Minimum Standards or Goals", and the development

of'requirements to demonstrate compliance". These will form the

basis of an initial draft of a ginning best practices document that will

then be distributed to all members of the ACGA for discussion and

comment.

The Workshop also generated significant comments, supporting or

qualifying the above, and these are included later in the full Report.

Potential areas for further research and development were also

identified, and these are noted in the report.

Overall, the project has demonstrated the following highlights: * The okra leaf trait was associated with superior field yield under raingrown conditions. That result is consistent with some leaf physiological water use efficiency measurements. * Full season types were superior for raingrown yield. Rooting depth was one factor associated with that result. * Some physiological water use efficiency traits have significant genetic differences and may be of value for use in choosing parents and/or screening segregating populations

Agricultural aircraft are of great importance to the Australian cotton industry. Specialised

aircraft are used to apply selected herbicides and fertilisers prior to planting, insecticides throughout the growing season and defoliants prior to harvest. The use of agricultural aircraft has developed largely as a result of the greater speed, better timing and efficiency of application offered by aerial distribution. Aircraft are able to apply agricultural products rapidly over large areas within narrow optimum application windows. When crop height and irrigated areas restrict the passage of wheeled vehicles, aircraft are able to place pesticides strategically on crops in response to economic thresholds, without contributing to soil compaction and breakdown.

Ultra Low Volume (ULV) application from the air has been used very successfully around the world for nearly three decades. The technique is used to effectiveIy apply insecticides in a range of crops including cotton, field crops and forestry. ULV pesticides formulated in low-volatile oil-based carriers are usually applied 'straight from the can' at total application rates of about 2-5 L/ha. This low rate of carrier is achieved by generating small droplets with a Volume Median Diameter (VMD) of approximately 50-100 um, usually using rotary cage type atomisers. Such droplet sizes allow large numbers of droplets to be generated resulting in high droplet coverage

(expressed in terms of droplet number per square cm) and high efficacy and productivity. This technology is particularly suited to the control of airborne pests (such as locusts and mosquitoes), forestry and broad-acre agriculture. ULV technology has been successfully utilised in the production of cotton in Africa, Asia and Australia.

Restrictions to the application of endosulfan in cotton were implemented by the National

Registration Authority for Agricultural and Veterinary Chemicals, (NRA) during 1999. In

particular, mandatory buffer distances and nozzle configurations were introduced. Despite the widespread adoption of these management tools and a successful season where an extensive monitoring of 14,000 beef carcases revealed only one carcase that exceeded the 1/2 MRL export endosulfan level further restrictions were imposed during july it is noted that low pest pressure and the use of products may have contributed to this finding. new rules for season suspended registration ulv formulation but permitted application existing stocks provided that: a) protection downwind buffer zone was doubled from 1500 metres to 3000 metres b) maximum allowed rotational speed micronair AU5000 nozzles reduced 4000 to 2000rpm. Based upon data compiled recent public domain studies undertaken on behalf land water resources research development corporation cotton report comments current practice establishing down wind distances nozzle criteria aerial ec products. examines available deposition assesses performance two mathematical models in predicting relative drift profile formulations endosulfan.

Indigenous Australian Gossypium species possess a number of attributes that could be used to improve the profitability of cotton cultivation in Australia (see CSP47C & CSP85C). The Australian eastern arid zone was poorly represented in the current CSIRO Cotton Germplasm Collection. The collecting trip funded by this grant provided the accessions needed to rectify this gap in the collection and expanded our knowledge of the natural biology of G. australe, G. bickii, G. nelsonii, and G. sturtianum. The herbarium specimens represent important source materials for natural biologists and Flora writers. The germplasm samples will be used in future studies of levels and patterns of genetic and morphological diversity among the arid zone Gossypium species. This in turn will provide a base-line for documenting the existence and directionality of gene flow among these wild cotton relatives

In the late 1980s, growing concern over the impact of irrigated agriculture on the surface and ground waters of NSW, lead the Department of Land and Water Conservation (DLWC), to conduct a water quality monitoring program in the Macintyre, Gwydir, Namoi and Macquarie valleys of NSW. This program commenced in 1991/92 and has been jointly funded by the DLWC and the water users of these valleys, whose on going concern, contributions and support are gratefully acknowledged.

There has been a heavy reliance on agri-chemicals in the Australian cotton industry over the past 20 years to increase production and profitability. The off-farm movement of these chemicals has created a number of environmental issues of concern for the industry (Edge, 1996). There is an urgent need for the development and adoption of management practices which reduce our reliance on chemicals and are agronomically and environmentally sound. Recent industry funded research has identified key transport mechanisms and highlighted the importance of storms and sediment in moving pesticides off-site. High risk periods include early season (when ground cover is low) and soon after chemical application (when field burdens of pesticides are high). Research in the grain industry has identified the capacity of stubble cover to reduce erosion and that winter cereals provide the most effective cover. Plot scale (<1ha) research in cotton found that a significant reduction in pesticide movement was achieved from surface treatments such as wheat stubble (Simpson et al, 1996 and Silbum et al, 1996). Our CRDC project commenced in June 1997 to develop management strategies to minimise offsite movement of pollutants at the paddock or farm scale. In particular, our goal was to apply the research findings with wheat stubble at the paddock scale and to assess the practicality and feasibility of this management practice.

The cotton industry is one of the largest user of pesticides among the Australian agricultural sector. It has been estimated that endosulfan and pyrethroids account for 70% of all insecticides. In addition to insecticides, herbicides are also used extensively to control the weed menace in cotton. However, reliance on herbicides to control weeds in cotton production system has the potential to cause concern about their presence in the environment and contamination of waterways. Recent monitoring conducted by the New South Wales Department of Land and Water Conservation (Cooper and Muschal 1998) show that residues of some herbicides are also being transported into rivers in cotton growing areas. The herbicides atrazine, diuron, prometryn and fluometuron have been detected consistently daring last three years of monitoring program in Northern New South Wales. The challenge for the industry is to cope with the public demand for clean and safer agricultural practices, reducing the environmental damage that is mainly on the excessive use of pesticides, while maintaining profitability. This article, as part of a new CRC research project we provide information that can help growers select herbicides that will have a minimum impact on water quality and sustainable cotton production. Some elements support for best management practices needed to sustain favourable environment to grow cotton is also presented.

Funding toward the purchase of an atomic absorption spectrometers (with flame and graphite furnace facilities). The instruments were purchased from Vanan Australia

last year for a price $109,755.80 and CRDC's contribution has been highly valuable in getting our chemical analytical facilities up to date. The new instruments have been used for the

analyses for a number of common elements including potassium, calcium, magnesium, sodium and several other elements for the research projects involving cotton industry.

The objective of NFF's trade strategy is to achieve a more profitable international trading environment for Australia's farmers. To realise this goal Australia has to expand its international lobbying effort for agricultural trade reform by harnessing the resources of NFF and Australian agribusiness and working with the Australian Government and like-minded industry groups in overseas countries.