In Australia, premature senescence (PS) is occurring with increasing frequency in cotton crops. By the time PS is noticed, it is generally too late to take corrective measures and the use of plant tissue testing as a diagnostic tool has not been widely successful in predicting K deficiency (Kerby and Adams, 1985). Therefore, it is important to detect beforehand susceptible fields, so that timely action can be taken to avoid substantial yield losses, as insufficient K is believed to be one of the main contributing factors of PS.

The Bourke region has experienced a dramatic expansion of irrigated agriculture, especially cotton production, over the last decade. For sustainable agricultural production, quantitative soil information is required for effective land management and environmental planning. There is therefore the need for updating the soil resource information of the region. Soil sodicity and structural stability are two soil quality indicators specifically investigated in this study. The study is aimed to assess the current levels of soil sodicity and aggregate stability in order to predict spatial patterns of these soil attributes with the view of identifying the risk zones. The effect of land use on the soil quality indicators is examined.

Field trial examining the use of Bacillus thuringiensis (Bt) foliar sprays on transgenic and conventional cotton varieties showed various levels of Helicoverpa control and impacts on beneficial insects. Quantification of Bt protein concentration at various growth stages of transgenic cotton varieties and bioassay with field strain of H.armigera revealed great variation of concentration and efficacy.

Elsewhere in this proceedings I have stated that the cotton industry in Australia is undertaking a journey towards the adoption of a true IPM. The industry has come a long way from indiscriminate use of synthetic insecticides to realising the major role natural enemies of cotton pests particularly predatory insects play in cotton IPM. Many beneficial insects such as predatory beetles, bugs, lacewings, spiders and parasitoids have been recorded in cotton crops in Australia. However, the potential value of these beneficial insects have riot been fully exploited in cotton pest management. This is due to the lack of understanding of the efficacy of these beneficial insects, lack of techniques to maximise their abundance and effectiveness, and the continuous use of broad-spectrum insecticides on cotton crops against major pests. Cotton fields across Australia are strictly monoculture and can affect the activities of beneficial insects. In such agro-ecosystems, pest populations increase, minor pests become major pests and non-pests become pests. This is because the food, hosts, prey, and hibernating or overwintering sites of the natural enemies are reduced thus affecting biological control (Mensah, 1997, 1999). Natural enemies of cotton pests usually have different food requirements in the larval and adult stages to develop and survive through the season. In contrast, adult pests particularly Helicoverpa spp. can normally lay their eggs without any feeding, relying only on food reserves transferred from their larval stage. Helicoverpa spp. are highly migratory and can rapidly infest cotton crops and lay their eggs. Unless natural enemies are present and well established in high numbers before the pest arrive, they cannot respond rapidly enough to control these pests (Fit, 1989; Mensah, 1997, 1999). This paper focuses only on predatory insects and how to incorporate them in pest management decisions.

We are currently evaluating unsprayed strip crops planted beside dryland INGARD cotton as nurseries for beneficial arthropods. In the first season of trial work (1999/2000) lablab was evaluated as a nursery (Scholz et o1. 2000). While lablab harboured some species of predators, it supported few Trichogramma egg parasitoids. Trichogramma wasps are considered important beneficials on the Darling Downs and a nursery crop that supports them, as well as other beneficials, may be useful for managing heliothis and other pests. Consequently, during the 2000/01 cotton season we evaluated unsprayed sorghum, maize and soybean strips as beneficial nurseries for adjacent lNGARD cotton.

In recent years late season populations of stinkbugs (green vegetable bug and green stink bug) have caused considerable damage in some cotton crops (Simpson et al. 2000, Khan and Bauer 2001). Over the past cotton season, in different valleys including the South Burnett and Macquarie, I or 2 insecticide sprays were required to manage Green vegetable bug (GVB). In Australia, the insecticides currently registered for control of stinkbugs are mostly non-selective and are disruptive to a wide range of beneficial species. Use of these insecticides during stage II of the insecticide Resistance Management Strategy (IRMS) therefore undermines IPM programs aimed at conserving beneficials. Therefore, the development or evaluation of less disruptive control tactics for stinkbugs is urgent. No soft chemicals are currently available, through a number of products registered for control of other pests are. One way of making existing chemicals less disruptive is by lowering their dose, but this is not always effective. In Brazil, a mixture of salt and lower dose of chemicals is being used to enhance efficacy of the chemicals to control GVB in soybean (Corso and Gazzoni 1998, Hugh Brier pers. communication 2001). The objective of this study was to evaluate the efficacy of existing chemicals mixed with table salt and to measure their impact on beneficial insects.

Unknown weeds may be identified from a collection of seed, seedling and adult pictures, or by leafing through the collection. The seedling collection has been structured with seedlings with similar leaf shapes grouped together.

The adult collection places weeds in the same order as they occur in the seedling collection. The seed collection is listed by seed size against a common scale, and secondly by real seed size.

The Assassin Bug, is a natural enemy that is showing considerable promise in controlling Heliothis and plant-sucking bugs in cotton. This paper is based on the collective results from several experiments where we examined the potential of this predator as a biological control agent in cotton. in recent field experiments, assassin bugs provided significant levels of heliothis and mind control and suggest that this predator may be a useful tool within an IMP program.

The Australian Cotton Cooperative Research Centre in association with the Cotton Research and Development Cooperation have funded a number of soil inventory projects which have produced enormous amount of soil data. The data have been incorporated into a queriable database using the Microsoft Access. Customised operations built into a Database Assistant enable variable queries to answer various soil quality questions that may be asked by researchers, farm managers, consultants and farmers, in retrieving appropriate soil data and information for a specific region/area and purpose. The soil data are geo-referenced and therefore are amenable to further Geographical Information System analysis

The Australian cotton growers for the past 5 years have come to realise the important role beneficial insects play in managing pests in their cotton farms. With a strong push by the cotton industry to adopt a true integrated pest management (IPM) programs, beneficial insects are increasingly assuming a major role in the cotton system. As a result, techniques required to maximise both the abundance and activity of this beneficial insects will continue to be a priority in the cotton industry. The use of beneficial insect refuges and most importantly the use of food supplements (food sprays) will become major tools in the Australian cotton industry as growers acquire more knowledge about a true IPM and the role of beneficial insects. The development of food sprays and the advent of the predator to pest ratio in particular has already educated growers about the need to conserve beneficial insects in the cotton system, and how to utilise them in cotton pest management programs.