objectives of the present work are the identification of the sex pheromones of Crocidosema plebejana and Pectinophora scutigera and the testing of synthetic candidate mixtures as attractants in monitor traps in the field.

The aims of the project were: * to test various versions of SIRATAC on a commercial scale. * to provide a database of the response of cotton to damage. * to compare the response of the new varieties Siokra and DP90 with DP61. Field work consisted of large scale trials on the leased Leitch block and small plot experiments using manual disbudding to simulated pest damage. The results of these trials were integrated with data from CS16L (The response of cotton crops to damage) and CS23L (Development Officers for SIRATAC) and made available to the industry at the Australian Cotton Conference (Kelly et at 1988). Further analysis of these results has shown that the capacity of the cotton crop to compensate for early season damage depends on the yield level. At yield levels common a decade or more ago (5 to 6 bales per ha) the crop could compensate but at current yield levels (7+ bales per ha) it is unable to do so. Furthermore Siokra is more tolerant to damage than DP90. These findings have been published in a series of three papers in the Journal of Economic Entomology (Brook et a1 1992, in press) and received rave reviews from the cotton entomology community. The abstracts of these papers are attached.

Any agent which reduces damage caused by heliothis is a valuable asset. In Australia we are fortunate to have several species of native parasites which attack heliothis, but not all of them are useful for within-crop management. Some parasites kill heliothis only after the larval stage has completed feeding, so in terms of crop damage, there is no difference between parasitised and unparasitised larvae. Current research at Toowoomba is investigating a native parasite, Microplitis demolitor Wilkinson [Hymenoptera: Braconidae], that kills heliothis during the fourth instar, before causing serious feeding damage. Results are presented on some aspects of this research. The release of two exotic species with attributes similar to M. demolitor is also discussed.

Nowadays, most of us are aware that natural enemies (parasites and predators) sometimes play an important role in the control of pests attacking our crops. As sure as heliothis will infest our cotton next season, we can be just as sure that parasites and predators will be there too - if they are given a chance! The problem is that we simply don't have the confidence to rely on natural enemies because we don't know enough about them. Where the risk is high, producers understandably are reluctant to take chances, and opt for the tried and proven method of pest management - insecticides. But this situation is changing. Resistance to insecticides has developed, human safety and the environment are major concerns, insecticide costs are increasing, and so on. We don't need to dwell on these issues. Opportunities are there to develop alternative management tools, and we must embrace their prospects.

Cottongrowers in central Queensland (CQ) enjoy no advantage over southern counterparts in the range of insect pests that attack their crop. Heliothis species, rough and pink-spotted boll worms, and mirids are major pests which damage the terminal buds and fruiting structures of cotton plants, potentially causing radical loss of yield and profit. While mites and tipworm generally are less active than in the south, a wider planting window means that adult forms of the soil insects that attack early-planted cotton seedlings are available to attack late-planted ones.

Previous research at Narrabri Agricultural Research Station and elsewhere has shown that mite populations increase more slowly on okra leaf cotton genotypes than on normal leaf genotypes (Bailey et al., 1978; Thomson, Reid and Fitt, 1984; Wilson and Pitt, 1987). Experimentally this difference has resulted in far lower yield reductions on Siokra than DP90 when artificial mite infestations were initiated in each variety at the same time. This paper summarizes the findings of experiments designed to determine the underlying cause of the resistance to mites found in the okra leaf genotypes and also reports some more recent findings

The cornerstone of most pest management programs world-wide is the "Economic Threshold" concept which is based on the principle of controlling a pest only if it is economically prudent to do so i.e. the cost of control is less than the value of yield loss caused by the pest. To implement this concept effectively three key criteria must be met. Firstly it must be possible to estimate the abundance of the pest accurately, secondly a rapid curative control must exist, such as an insecticide or miticide, and finally the relationship between the abundance of the pest and reductions in the economic value of the crop must be known. All of these criteria are now met for mites on cotton in Australia.

At the last ACGRA conference in 1990, it was reported that the Heliothis ID project had been running for approximately six months and species specific antibodies had not yet been obtained. Here we report the production of suitable species-specific antibodies, the design of a prototype kit, some successes and problems encountered in field trials and current work being undertaken to develop the kit to a commercial standard.

Helicoverpa punctigera (Wallengren) and H. armigera (Hubner) have a number of characteristics which make them highly successful pests of numerous crops in Australia, including cotton (Fitt 1989). They are highly mobile, have a broad host range and can increase in numbers rapidly when conditions are favourable. Current pest management relies on regular sampling and application of pesticides when thresholds are exceeded. It seems unlikely that the need for regular crop checking can ever be abandoned, but here we discuss prospects for predicting changes in Helicoverpa abundance which may assist pest managers in the future

Nutgrass (Cyperus rotundus L.), a plant native to India, is known as the world's worst weed . It is a member of the family Cyperaceae, which contains approximately 3000 species, of which about 220 species are important weeds . Nutgrass is cold sensitive , only growing during the warmer months and will not survive in the colder parts of Australia. It is adapted to most soil types and soil moisture regimes