Discusses irrigation in Australia in the context of global food security, decreasing water resources and the contribution of research and development to innovation.

Over the past two hundred years we have physically and biologically degraded many Australian streams. Catchment managers at the end of the millennium face two daunting tasks: how to minimise further damage to rivers and streams, and how to repair the damage that has already occurred. We can return natural values to our waterways. This manual is designed to help those professional managers who are accepting the challenge of rehabilitating the physical and biological condition of Australian streams.

This report aims to summarise current and proposed GMO activities and make suggestions on targeted research investment that might better prepare Land & Water Australia (LWA) to help manage these new resources. This is despite the obvious limitations of trying to foresee the implications of such a new and broadly applicable form of technology.

On the whole, this research project showed that Australian farmers are alert to new weeds, and have a reasonably high level of commitment to their detection and control. As a group, farmers therefore need to be encouraged, and equipped to be vigilant and effective weed spotters. This may be achieved through training opportunities, greater extension and educational activities, increased resources devoted to weed detection, and greater cooperation between landholders and weeds authorities.

Stopping seed-set on weeds that have survived a treatment of glyphosate is an important part of an IWM approach to preventing the development of glyphosate resistance. The double knock method of seed-set prevention to avoid or significantly delay the evolution of glyphosate resistant ryegrass has been used successfully in southern Australia. The double knock tactic involves the use of sequential knockdown herbicide applications from different herbicide mode of action groups. This method has been developed so that survivors of the first herbicide application are controlled by the second

When comparing BollgardII with conventional cotton, the lower water requirement and higher lint yield of Bollgard II was explained by greater insect damage in conventional cotton. The effect of this damage was to delay time to maturity and increase leaf area of the conventional variety, which in turn increased crop water use. In situations where pest damage is minimal, variety differences are unlikely or could favour the conventional variety where tipping is the only damage. Water stress equivalent to extraction of > 60% of plant available water at mid flowering and cut-out reduced Bollgard II yields by 24 and 36%, compared with 2 and 17% in conventional. A much higher boll load at the time of stress prevented compensation in the BollgardII variety. Over 2 seasons the response of BollgardII to different irrigation frequencies (deficits) was strongly influenced by evaporative demand. Where the deficit was about 80mm (40% of PAWC) yield was increased by 20% in the lower evaporative demand season. The yield difference was minimal with a deficit < 40mm (20% of PAWC). Generally Bollgard II produced consistently higher yields at smaller deficits (35 to 54mm). However yield at a 35 mm deficit was reduced in 2007 / 08 by rainfall coinciding with irrigation.

OBJECTIVES Reason for Travel Dr Denholm is an international authority on the management of resistant Bemisia tabaci on cotton. 1. Funds were requested to bring Dr Denholm to Australia to present a keynote address on whitefly management at a special cotton entomology symposium at the Australian Entomological Society's Scientific Conference, Tamworth 23 -28 th September 1995. 2. Dr Denholm was also requested to address a CRDC/HRDC Workshop on Biotype B Bemisia tabaci in Australia, discussing the options for the management of resistant B. tabaci on cotton in Australia, held at the Airport Hilton, Sydney 10October1995. 3. To discuss progress in collaborative research on B-type B. tabaci and Helicoverpa resistance biochemistry between Dr Gunning and the Rothamsted Insecticide Resistance Group

The position of Cotton Industry Development Officer (C.l.D.O) in the Macquarie Valley was implemented in 1993-94 because much good research generated at Narrabri was not being adopted by local growers. The reason was that there existed a perception that this research was not relevant to the conditions in the Macquarie. There was also concern that trials carried out in small plots did not accurately represent farm scale production.

OBJECTIVES 1. To undertake a comprehensive sutvey of the Australian distribution of B. biotype B. tabaci . 2. To sutvey cotton for the presence of B, biotype B. tabaci 3. 4. To develop and asses the usefulness of a field "squash test" to identify B -biotype B. tabaci. To undertake preliminary bioassay studies to identify insecticide resistance status of this insect.

Cotton plants expressing the CrylAc toxin from Bt are near to commercial release. These plants have been developed to aid in the control of heliothis caterpillars, the primary target of insecticide usage in cotton production. Despite initial hopes, the plants will not give season-long control of heliothis. Late in the season, heliothis grubs can survive and grow on transgenic cotton plants. Thus, in these mature plants either the amount of Bt toxin is lower than it was earlier in the season, or the Bt toxin is partially inactivated by the leaf. The decline in the efficacy of plants late season makes resistance management more difficult than if expression of the toxin was maintained at a high level. This project examined the potential of transgenic Bt plants to select for resistance to the insect pest Helicoverpa armigera. We have focused on gaining an understanding of why the plants are able to control heliothis caterpillars late in the season. It is at this time that selection for resistance may well be at a maximum. At the beginning of our study nothing was known about the cause of the decline in toxin levels, nor were techniques available that would enable us to quantify those levels. Thus, we have had to focus on developing the necessary techniques to study the performance of transgenic plants grown under field conditions. We have successfully developed a leaf bioassay test that can measure relative changes in toxicity of Bt leaves. We observed a 3-fold decline in toxicity of the plants from young plants, before budding, to mature plants with bolls. This decline is only small so it suggests that the level of Bt toxin in young cotton plants may not be much above the level to kill heliothis. A number of additional factors were observed to affect the efficacy of the Bt. The potency of Dipel 2X was reduced to half when it was fed to larvae in a soy bean based diet, compared with one of chickpea. Some component of older leaves also appears to reduce the availability of Bt toxin to larvae feeding on a mixture. Preliminary experiments also indicate that stressing plants may also affect Bt levels, although further experiments are being carried out to elucidate the precise factors. In a second phase of the project we have attempted to develop a strain of H. armigera resistant to Bt We have modified and developed a technique that produces mutant H. armigera. These mutants have been screened for individuals carrying Bt resistant genes. One candidate resistant strain has been established. Although its level of resistance to Dipel is low, it appears to survive better on transgenic plants compared with controls. We are investigating this strain further.