Has the introduction of Bt genes into the cotton plant affected its capacity for compensation after insect damage? This question is relevant for three reasons. First, and most obviously, Bt cottons remain vulnerable to non-Iepidopteran pests, including thrips and minds. Second, they are susceptible to Helicoverpa spp. when Bt efficacy drops because of crop ageing. Third, under some (yet undefined) environmental conditions, Bt efficacy can be low even in young crops, and we have seen fruit shedding in young commercial Bt crops that has been attributed to Helicoverpa damage. We assessed the degree of tolerance of Bt cotton to actual and simulated insect damage in three field experiments carried out at ACRl in 1996/97. Yield and maturity responses to damage of Bt cottons compared well with those of conventional varieties. The introduction of Bt genes into cotton does not seem to have reduced the considerable capacity of the crop to tolerate insect damage, and this attribute should be considered in the development of pest management strategies for Bt crops.

In some major producing countries, up to half of the returns to cotton farmers come from government subsidies. In some cases, the subsidies are counter cyclical so that the recipient farmers never face the realities and disciplines of the world cotton market. These countries also maintain substantial barriers to imports of yams, textiles and clothing. The consequences of highly protective policies for non-subsidising countries are disastrous. When international prices start to fall, there is no supply response in countries, such as the United States, which heavily subsidise their producers. The subsequent over-supply greatly exacerbates the downturn in world prices so that all the adjustment is forced onto non subsidising countries. This in nun causes significant social disruptions, particularly in developing countries.

VAM are important in the growth of cotton and the production of lint. VAM are a normal part of cotton plants and they are usually present in the roots. Only in their absence do we realise their importance. In syndromes like Long Fallow Decline or growth decline following land-planing, reduced plant growth and cotton production coincide with reduced VAM in roots, and reduced phosphorus content in mature plants. While we realise their importance, VAM are difficult to study. VAM are an association between soil-borne fungi and the roots of most plants. For the fungi, the association is obligate, and growth of the fungi relies entirely on the host plant. We cannot see the fungi in soil, nor in the roots of the plant unless we use laboratory based processes. Thus study of the fungi and their effect on plants requires specialised equipment and trained staff. CRDC has funded VAM research for several years, This paper summarises the research on the population biology of VAM fungi in cotton soils in eastern Australia completed at the University of Sydney.

(I) To continue and develop the work begun in UsQ6C which focuses on residue handling in back to back cotton and rotation crops while optimising the control of diapausing heliothis pupae. (2) To visit growing areas (irrigated and rain fed) and confirm a basis for other machinery needs in the industry, including planting and cultivation equipment. (3) Field test equipment changes. (4) Seek backing from commercial entities to limit funding drain of research monies. (5) Pursue the involvement of commercial manufacturers where appropriate to help in the adoption of improved technology. (6) To monitor commercialisation of a fully tested computer based guidance system

Farming systems are continually attracting interest amongst the growing community, since input costs are continually increasing and returns behave in a cyclic nature. Growers are now stepping back from the enterprise, to assess the production unit for agronomic, economic and environmental issues before selecting the rotation crop for the farm, endeavouring to achieve the most sustainable production system. This has research dollars invested, to examine the effects of rotation crops on the cotton production system.

The adoption of integrated Pest Management technologies and strategies, which are being extensively researched and developed in the cotton industry, has been very limited. The development of effective extension programs is totally dependent on an understanding of the attitudes of growers and consultants to PM. The Cooperative Research Centre for Sustainable Cotton Production supported a Special initiatives project in 1997 to investigate the Attitudes to Integrated Pest Management in the Cotton industry.

Microplitis demolitor (Wilkinson) (Hymenoptera: Braconidae) is a critical component of IPM in Australian cotton. High rates of parasitism (up to 65%) occur naturally in the field at a crucial stage in the development of the crop. Parasitised larvae cause negligible damage to the crop. M demolitor adults were demonstrated to tolerate certain insecticides (chlorfluazuron methoxy fenozide and pirimicarb) but were very susceptible to many others (endosulfan<dimethoate< cyhalothrin< profenofos< deltametlirin< bifenttirin< spinosad). M. demolitor is extremely tolerant of most insecticides during the pupal stage. Larval M. demolitor were not directly affected by insecticides but survival was reduced due to host mortality. Susceptibility of the host to stomach insecticides was reduced about 5 days after parasitisation, while insecticides with a contact action caused host mortality throughout the parasitoid's larval stage.

This topic goes to the heart of the current crisis in the Australian cotton marketing system. The cotton industry is currently in a state of shock. This shock stems from the collapse in both the Australian dollar and the Us cotton futures market. A number of growers have not survived. Many more are looking at massive losses due to buying the Australian dollar forward and not selling cotton futures forward. Big swings in markets highlight bad marketing practices. Hopefully the industry can learn from this difficult time. More importantly, we can only hope that the litigation currently underway will not destroy the Australian cotton marketing system as we know it and enjoy it today. The Australian cotton marketing system is arguably the most advanced agricultural marketing systems in the world. The current crisis centres on the collapse of the Australian dollar, the collapse of the cotton price and the selling (hedging) practices of scores of cotton growers. These growers had bought (hedged) the Australian dollar in the 60-65 Us cent area, some out for five years, They saw that as good income protection. But they did not sell (hedge) the US dollar cotton price. Over the past 18 months it slipped to a 30 year low. A number of cotton growers are now bankrupt. So far industry-wide bad debts could top $A30 million. Now, a number of cotton growers are refusing to honour contracts with cotton merchants. The cotton merchants, like Namoi Cotton, Queensland Cotton, Dunavaant and Colly are left holding the can. So this is a difficult time, but an important time, to talk about how to survive in a volatile environment

In cotton, phosphorus (P) is important for early seedling vigour, plant establishment and root development. Deficient plants are usually stunted, dark green in appearance and exhibit a delay in flowering, bon set and maturity (Hodges, 1992). The main role of P in plant metabolism is to allow energy transfer to occur(Mengel and Kirkby, 1987). Research by Macleod et al. (1997) has shown that P may also be involved in the onset of premature senescence. When cotton plants are subjected to environmental stresses such as waterlogging late in the season, the rates of translocation of P and K from leaves and other organs to the filling boils, is greater than the rate of uptake from the soil solution, which in turn leads to a reduction in the efficiency of these supply organs and causes the plants to senescence prematurely

Most crop plants suffer a decline in growth when exposed to saline conditions although cotton is classified as a salt-tolerant crop. Although there has been extensive study of the effect of salinity on cotton at germination and during seedling growth there is less information on the effects of salt on the overall growth of the cotton plant. The effect of salinity on yield has been considered but there is limited information on the effect on fibre quality. Several cultivars are being studied to examine the effects of different salts on various stages of development of the cotton plant.