Key factors in managing transgenic Bt cottons for the future are to have an effective resistance management strategy. An essential component of any such strategy is to establish a resistance monitoring program. The core components of this project address resistance monitoring as well as examine the performance of transgenic cotton (two genes) in relation to resistance management.

NSW Agriculture initiated the industries Bt resistance monitoring program in 1993. Intensive monitoring of Australian field populations of Helicoverpa armigera and Helicoverpa punctigera began in 1997 following the commercial release of the Bt transgenic crop, Ingard®. This report summarises results of the Bt resistance monitoring program between 1999 and 2002 and discusses possible directions for future research. In conducting the resistance monitoring program eggs are collected from all cotton growing districts throughout the season.

It is known that expression of the Bt protein, that produces the toxin Cry1Ac, declines throughout the crop cycle. The highest levels of protein expression occur during the early squaring (pre-flowering) period of growth. It is expected that this period also corresponds to maximum selection pressure against the toxin Cry1Ac. Although the decline in the Bt expression during the last half of the crop cycle reduces field efficacy against Helicoverpa spp selection for resistance is still expected to occur, thus Cry1Ac is under constant selection pressure.

One of the aims of this project is to assess the N fertiliser requirements of cotton under more enlightened tillage systems currently being adopted. The application method for nitrogen fertiliser may change as the tillage system changes. For example, true minimum tillage is inconsistent with an anhydrous ammonia application shank working down the centre of each hill at 20 to 30 cm depth, particularly in wet soil. The alternatives are often less convenient than the traditional method and to date there has been little research in comparing methods of application. Results for the first two seasons of this experiment are summarised in this article.

Helicoverpa armigera (Hubner) and H. punctigera (Wallengren) are serious pests of cotton in Australia. These pests constitute a continually increasing production cost for most field crops,

particularly cotton. At the end of the 1996-97 cotton season, cotton growers in the Emerald, Biloela and Theodore areas of CQ agreed to adopt a trap-cropping program as a first step in

the development of an area-wide strategy for management of Helicoverpa.

The principal research objectives of this project were (i) To review the strategic framework and test the validity of ecological assumptions underlying the CQ trap-cropping program, (ii) To develop indicators for assessing the efficacy and impact of trap crops, and (iii) To determine field parameters for optimising trap crop deployment and trapping efficiency under local field conditions. These objectives have all been achieved to varying degrees,

The research outputs of the project show that the CQ trap-cropping strategy is based on sound ecological principles. The strategy seeks to exploit weaknesses in the regional population dynamics of Helicoverpa. The fundamental assumptions underlying the strategy are valid.

The Helicoverpa problem in CQ is to a great extent locally generated within the cropping system. This explains the measurable rise in the level of insecticide resistance in the pest. Host plant bottlenecks are clearly important factors in the population dynamics and pest status of Helicoverpa. This project has shown a relationship between spring rainfall and the incidence of resource bottlenecks in spring, namely, the correlation between spring rainfall and the incidence of Helicoverpa on cotton crops. Within cropping systems, spring resource bottlenecks, if and when they occur, are important determinants of Helicoverpa pest status early in the spring/summer cropping season.

The silverleaf whitefly (Bemisia tabaci B type) is a world-wide pest on many crops, with a particular appetite for cotton.

Although the SLW has reached pest status in the horticultural industries of the Northern Territory and Queensland, the cotton industry in Australia is not affected by the silverleaf whitefly. However, the presence of this pest in Australia's cotton growing areas and the current worldwide problems associated with SLW management, has presented the industry with a potential disaster.

Is it a matter of time as for other countries? Is Australia's climate suitable? Is cotton

a good host? Are competition and predation our saving grace? These and more detailed questions need to be addressed. Australian cotton growers and researchers may then play a role in either; keeping the present situation as it is (if the SLW has simply not been able to establish). Or, by not providing the pest with a chance of a foothold if the opportunity still awaits.

Outbreaks of SLW in other countries have been studied, and theories have been presented as to the development of its major pest status. Major theories include the effect of climate, reduction in beneficials, poor insecticide management, and changes in fanning practices including the increase in suitable hosts.

Most of these factors we can examine to enable us to identify the risks that would elevate the SLW to a major pest in Australian cotton.

In recent times cotton growers have seen the need to adopt new land preparation practices. In the Macquarie Valley alone, only 35% of the 1987/88 cotton crop was prepared using conventional techniques. The swing away from conventional land preparation practices has largely been in response to economic factors. However, a further factor is the greater awareness growers have in relation to maintaining and improving their soils structure. Much of this awareness has been as a result of excellent research and extension programmes. In this paper l will be dealing with the research and technical inputs which have led to innovative land preparation practices.

Profenofos resistance is due to esterase mediated metabolism. Preliminary research suggests that an insensitive acetylcholinesterase is also involved. However, during the course of these experiments, the resistant strain being used lost its resistance. The strain has been replaced and all experiments are being repeated to verify these results.

Preliminary research indicates that ‘knock down resistance’ (kdr) is not involved in bifenthrin resistance, although further experimentation is needed. It is thought that metabolic resistance mechanisms are involved.

Research into potential resistance mechanisms to endosulfan (no endosulfan resistant cotton aphid strains are available yet, so any current research is speculative) indicate that esterase mediated resistance may be involved. Preliminary research indicates that an insensitive AChE is not likely be involved.

Research has also been done to determine whether aldicarb and carbosulfan can be separated into two separate groups in the resistance management strategy. This has turned out to be a very difficult problem to solve. Preliminary research indicates that the two chemicals could be separated out without a great risk of cross resistance occurring.

One of the major milestones was the development of a field based kit to detect pirimicarb resistance in cotton aphid populations. This kit identifies pirimicarb resistant cotton aphids by a simple colour change - squashed resistant aphids turn yellow, susceptible aphids stay clear. This kit provides the grower valuable information in making spray decisions.

H. armigera populations on cotton have been exposed to BT toxin from sprays and transgenic cotton for a number of years and a CRY 1Ac tolerant strain the “Silver strain” was bred by Dr HT Dang, from the survivors of the CRY 1Ac resistance monitoring programme. There has been some controversy over the CRY 1Ac resistance status of the “silver strain”. This controversy has been exacerbated by BT bioassay methods with a poor delivery of toxin to larvae and hence a poor dose response relationship. As this research project about the apparent ability of the “silver strain” to metabolise C RY 1Ac, is dependent on the assumption of resistance, we have done some research to improve BT bioassay methods and toxin delivery to the insect.

in the Gwydir Valley where the water resource has been over committed to such an extent that a full allocation of water will only be realized only SO years out of every 100 years. Using these parameters I will attempt to outline a few procedures we try to abide by.

Transgenic cotton was introduced to Australia in 1996 with Ingard® which was replaced by Bollgard II® in 2004/05. Transgenic cotton is now grown by over 95% of Australian cotton growers so is an integral part of the Australian cotton industry, helping enable the industry to dramatically reduce insecticide use by 89% (Australian Grown Cotton Sustainability Report 2014).

The cotton industry has been able to work closely with the commercial companies involved and regulatory bodies in developing resistance management plans and monitoring the performance of the technology primarily through the TIMS committee and research organisations. However the stewardship of the technologies at a grower level has been largely the responsibility of the commercial companies.

An industry need was identified for the delivery and promotion of independent industry research focused on resistance to GM cotton and the effectiveness of commercial stewardship programs to ensure the protection of the technology for future industry use.

Bee hives are sometimes placed near cotton fields where there is a risk that they will be exposed to pesticides such as fipronil. In recent years there have been instances of bee death that have caused concern for beekeepers. At the same time it has been suggested that the cotton crop benefits from honeybee pollination. The cotton industry needs to gather information regarding the risks that pesticide application poses to beekeepers and whether the benefits from honeybee pollination are significant enough to incorporate into practice.

The key focus of this project will include a review of the existing literature into the pollination effect of honey bees in cotton. The review includes a summary of the mating system of upland cotton, a summary of the production benefits detailed in the literature an evaluation as to the benefit of bee pollination in cotton, attractiveness of cotton to honeybees and an evaluation of the contribution of pollen beetles to pollination of cotton.

Outcomes include the need to accurately quantify the contribution of honey bees to cotton pollination as well as further determining methods to better mitigate risks to bees. Risk management needs to be conducted with Cotton Australia and Industry as well as with the bee industry with honey producers acknowledging their responsibility to inform cotton growers of hive placement and potential challenges for bees around cotton farms.