Transgenic (Bt) cotton varieties provide a substantial basis for economically and environmentally sustainable insect pest management within the Australian cotton industry. The introduction of Bt cotton has significantly reduced pesticide use for the control of key pests such as Helicoverpa spp. and encouraged a greater emphasis on the management of beneficial invertebrates in pest control. A major risk now facing the cotton industry, from a pest management perspective, is the development within H. armigera of resistance to Bt. As a result, mandatory requirements are placed on growers of Bt cotton to provide refuge crops (no Bt exposure) as sources of susceptible moths that will mate with any potentially resistant moths arising from the Bt crops – thus swamping resistance development. Various refuge crops are available as options (pigeon pea, maize, sorghum, conventional cotton). To properly evaluate the utility of such refuges, we need improved knowledge of the degree to which moths generated by them and those emerging from Bt crops effectively mate. A core assumption of the current Bt Resistance Management Plan for Bt cotton is that moths from different crop origins mate at random. Using carbon isotope signatures characteristic of C3 and C4 plants (e.g. cotton and pigeon pea cf maize and sorghum), this project demonstrated that mixed matings of Helicoverpa moths from such different plant host origins can be common on the landscape, but the assumption of random mating in such instances may not strictly be true. More research is planned to further confirm these conclusions.

This project also continued monitoring of long-term (and seasonal) changes in Helicoverpa abundance in cotton growing regions through networks of pheromone trapping in the Namoi Valley and St George / Dirranbandi regions that began prior to the introduction of Bt cotton. The pheromone trap catches for H. armigera in the Namoi Valley suggested this species has increased in abundance (at landscape scale), especially late in the cotton growing season, since the advent of Bt cotton. The mechanisms driving such change are not understood, but could be related to reductions in pesticide use and / or concurrent variations in the use of other crops on the landscape that are attractive to the moth. The abundance of H. punctigera has also increased in the last few years. Spring surveys of crops, weeds and native vegetation showed promise as early warning indicators of the forthcoming seasonal bias in Helicoverpa spp. in cotton crops.

Concurrent with our work on Helicoverpa, we opportunistically gathered data on the abundance of secondary cotton pests and beneficial invertebrates within refuge crops and their associated Bt cotton crops. Refuge crops (especially pigeon pea crops which were the focus of much of the work done in this project) supported substantial populations of mirids and predatory beetles and bugs. The balance of effect of such pests and beneficial species for cotton production needs further study with respect to movements to cotton crops and the hindrances beneficial species may provide to effective Helicoverpa production within refuges.

In addition, we explored the potential of jasmonic acid, a chemical involved in plant response to herbivore damage, to act as an attractant for beneficial invertebrates in cotton crops. Such responses have been suggested by overseas research. Identification of attractants for beneficial species could provide useful tools to enhance IPM in Australian cotton systems. However, jasmonic acid failed to influence aggregative behaviour of beneficial invertebrates in trials we conducted in conventional cotton fields.

Green mirids (Creontiades dilutus) have emerged as a significant problem in commercial Bt-cotton crops, especially in Bollgard II crops. This is believed to be due to the reduced spray regimes in these crops, which allow mirids to survive and reproduce, where in the past they were co-incidentally controlled by insecticides applied against the primary pests Helicoverpa spp. Our past experience with mirids has been as early season pests, and although thresholds were available it was not known if these were appropriate for populations occurring later in the fruit setting and maturation period. The level of damage to fruit that can be tolerated without yield loss was poorly understood and this undermines confidence in tentative thresholds and encourages growers and consultants to use low thresholds. This can lead to increased costs, disruption of beneficial population and increases the risk of outbreaks of secondary pests such as silver leaf whitefly, spider mites and aphids. This project investigated the effect of late mirid damage to young bolls through the early, mid and late fruit set and maturation period, using real and simulated damage (boll injecting with weak pectinase solution). The results of a range of glasshouse and field experiment show;

1. Boll injecting was a useful tool to simulate damage by mirids, though the damage caused is more severe than that caused by mirid feeding.

2. Cotton was able to recover fully from damage inflicted in the early fruiting period (3 weeks after flowering began) when damage of 5 or 20 bolls per metre was inflicted.

3. Damage in the mid (5 weeks after flowering began) or late (8 weeks after flowering began) tended to reduce yield at heavier levels (20 or 50 bolls damaged per m) but had no effect at 5 bolls per m)

4. Yield reductions were due to reduced gin out-turn, resulting from selective removal of damaged lint, reduced boll numbers (in some cases), and reduced boll size of damaged bolls.

5. There was strong evidence of compensation for bolls shed due to injecting. This compensation was due to retention of extra undamaged bolls which partially made up for those shed due to damage. In the heavier injection treatments it is possible that too many bolls were lost for immediate replacement by substitution, possibly explaining reduced boll numbers.

There is now a large data set available which can be used to test and calibrate the OZCOT model, which can then be used to generate ‘rules of thumb’ for the degree of damage that can be tolerated. This can also be used as part of a decision support system which integrates mirid information with the wealth of research already captured in OZCOT, allowing interactions between growth, climate and pest damage.

The production guide for the growing of dryland cotton in Australia (third edition, 2002). The precursor to the current Australian Cotton Production Manual (updated annually).

This paper discusses recent progress with the refinement of promising methods, both direct and indirect, for measuring the severity of compaction in cracking clays used for irrigated cotton. It should be read in conjunction with the companion paper by Greenhalgh et al., in these proceedings, which summarizes the results of a preliminary evaluation of methods. Both studies are funded by CRDC as part of project DAN SOC; 'Refinement of soil physical assessment procedures'.

In Australian cotton fields, the eggs, larvae and pupae of Helicoverpa armigera and H. punctigera are attacked by a diverse range of parasitic wasps and flies. These parasitoids help to reduce the overall abundance of Helicoverpa in the agroecosystem by removing a proportion of the developing populations (Fitt 1994 Anit. Rev. Entomol. 39:543-562). However, despite their importance, our knowledge of the biology and ecology of many key parasitoid species is severely lacking. While research on Trichogrammatid wasps and Microplitis demolitor has provided detailed information on biology and ecology of these parasitiods (Scholz 1990 Msc thesis, Uni. Queensland pp203) other key species have never been studied. For example, although Heteropelma scaposum, is often the most abundant Helicoverpa parasitoid encountered in the cotton agroecosystem (Fitt and Mares 1992 Proc. 6" AUSt. Cotton Conf pp 269-276, Fitt and Walker pers. obs. ) nothing is known about the biology or ecology of this wasp. Furthermore, we have little information on the habitat requirements of Ichneumon promissorius, a true pupal parasitoid of Helicoverpa recently exported and successfully established in the USA for control of H. zea in corn crops.

New technology may increase the importance of parasitods by enhancing their numbers. The development of transgenic varieties of cotton producing Bt proteins has been a major advancement in the fight against Helicoverpa spp. As part of the management plan to reduce the chance of Helicoverpa spp developing resistance to Bt, the use of refuge crops has been endorsed. The use of refuge crops, while designed to produce more Helicoverpa (Fitt 1996 Proc. 8" Allst. Cotton Goof pp 69-76) may inadvertently increase populations of egg, larval and pupal parasitoids. Slimlarly, the practice of planting pigeon pea as a trap crop for Helicoverpa in transgenic cotton (Anon. 1997 AUSt. Cotton Grower 18:82) may significantly increase egg and larval parasitoid populations. If so, can these parasitoids originating from refuge or trap crops be attracted back into the transgenic cotton crops to parasitise late season Helicoverpa larvae or pupae thus further lowering the chances of resistance to Bt protein developing?

The aim of this project is to gain a more comprehensive understanding of the biology and ecology of key Helicoverpa parasitoids, and thereby indicate ways of effectiveIy augmenting and conserving parasitoid populations in cotton using the most appropriate management techniques.

The cotton aphid, Aphis gossypii is a pest of escalating concern in Australia. With increasing utilisation of Bt cotton and consequent reduction in insecticide applications, coupled with emerging insecticide resistance, cotton aphids appear to be more of a problem than previously. The cotton aphid also has been shown to carry, or cause, a new major problem for the Australian cotton industry, cotton bunchy top. Fundamental to the development of IPM systems for cotton aphid is the knowledge of what biological control agents are active and their relative importance.

The cotton aphid paresitoid, Lysiphlebus testaceipes released in Australia in 1984 has recently (2000) been found attacking corn aphids on sorghum in cotton areas in Australia. The paresitoid more recently (2001) has been recorded from

the cotton aphid in Australia. However no systematic survey to determine its abundance and importance has been carried out. This parasitoid was recently rated by USA cotton IPM specialists as the most important paresitoid of all those attacking pest insects in cotton in the USA.

Two other aphids (the green peach aphid and the cowpea aphid) also occur in cotton. Nothing is known about how the natural enemies of the different aphids interact and influence the biological control of each aphid species.

Trap crops are an important part of cotton production. Other aphids in trap crops including the cowpea aphid, soybean aphid and corn aphid may also play an important role in providing a refuge for biocontrol agents of aphids in cotton. Trap crops may be able to be manipulated and managed to provide beneficials for aphid control in cotton.

Aphid parasitoids in other agroecosystems have provided effective biological control of aphids (eg. Iuceme in Australia and wheat in South America). The new parasitoid, L testaciepes may be able to provide effective biocontrol of cotton aphid in Australian cotton.

Helicoverpa spp. moths continue to pose significant pest management problems for Queensland cotton growers. To address the Helicoverpa spp. problem the Department of Primary Industries (DPI) was successfulin securing funding from the Queensland Treasury for a new initiative entitled Supporting Green Industries. The objective of this new initiative was to develop new tools and techniques that could be used to better manage Hencooerp" spp. more sustainably and reduce the cotton and grainsindustries dependence on insecticides.

A significant feature of the new initiative was the establishment of Biopesticide and Chermical Ecology Units led by Dr's Caroline Hauxwell and Chiis Moore

respectively. These units were chartered to investigate and develop biopesticides and chemical compounds that have potential for Helicoverpa spp management.

The purpose for this project was two fold. A major objective was to field test and evaluate the technologies developed by the Biopesticide and Chemical Ecology units. The second objective was to develop and test novel field control options for Helicoverpa. spp that could be incorporated into an Area Wide Management program for Central Queensland.

The purpose of the travel was to present a talk entitled “Wet Roots? High resolution groundwater depth prediction in the Bourke Irrigation District” at the 9th international River Symposium in Brisbane. I was representing the CCC CRC as a finalist in the Young water scientist of the year award 2006. The competition was a national one open to all CRC students undertaking research into a water related topic.The major outcome and highlight was winning the National award for 2006. The award was judged both on a written submission as well as the presentation. In addition to this I gave a plenary speech after accepting my award. A major outcome was demonstrating to the wider community that the cotton industry is actively addressing the i to do this.

Cotton has been looked to be a commercial crop in the Northern Territory on several occasions over the last 100 years, firstly as a wet season crop and more recently (in the last 25 years) as a dry season (winter) crop. The recent success of a hybrid model of crops planted in the wet and finished in the dry at Kununurra and the developments in the Georgetown region of Queensland has reignited interest in growing cotton in the Northern Territory.

A few commercial crops have been planted as well as demonstration crops at Katherine Research Station. The main issue in the Northern Territory is a complete lack of understanding of the cotton production system and to an extent, limited exposure good agricultural practices associated with broadacre farming as there has been limited development of a cropping industry in the Northern Territory.The Projects objectives were to introduce new and potential cotton growers to the best practise methods for cotton from the Southern Queensland and Northern NSW growing regions. With a focus on both dryland and irrigation, with an emphasis on the most suited irrigation methods for the Northern soil and climatic conditions.

Other important factors to be investigated will include crop management, surface water development and the development of a cropping system that has cotton as a cornerstone crop.

This project was established to look at various aspects of insecticides in cotton and the factors that would directly affect decision making. Helicoverpa spp. are still the primary pests of cotton in Australia. Chemical control available for these pests consisted of a limited selection of conventional insecticides. These insecticides were from key chemical groups still used by the industry include carbamates, organophosphates and synthetic pyrethroids and because of their broad-spectrum activity they significantly disrupt most predators and parasites (Wilson et al., 1998), and in some cases have a negative environmental impact. Frequent chemical spraying resulted in the development of resistance to some of these chemicals by Helicoverpa spp., eg. carbamates and synthetic pyrethroids. To counter resistance issues, new insecticides are being developed and registered for control of Helicoverpa in cotton. This new generation of insecticides are promoted as being more selective, less disruptive to beneficial and therefore more compatible with IPM (Holloway, J., Forrester, N., 1998). Cotton growers now have the choice of selecting from “old” and “new” insecticides when deciding to apply insecticides. Knowing the efficacy of individual insecticides against the target pest species is insufficient to make these decisions. It is also important to have knowledge of how these insecticides impact on other pests, predators and parasitoids. Strategic use of conventional insecticides in an IPM strategy will not only assure their efficacy but also prolong their existence for cotton insect management programs. Therefore, “old” and “new” insecticides should be rotated and placed in a way that they will perform effectively and soundly within the integrated pest management (IPM) and the integrated resistance management (IRM) strategies.