This project derived from a previous Australian Cotton CRC project, &quote;Plant-based attractants for Helicoverpa moths and sucking pests of cotton&quote; (Project 2.2.9). It investigated ways in which the behaviour of Helicoverpa spp. and the sucking pests, the green mirids, can be manipulated in a cotton landscape which includes transgenic and conventional cotton, refuges for resistance management, beneficial nurseries and non-crop vegetation. The project generally aimed to develop plant-based attractants or repellents for cotton pests, including further refining and commercialising our current product, Magnet®. Specific objectives were: (1) to develop field bioassay methods for mirids, (2) identify plant volatiles attractive to mirids, (3) investigate potential for mating disruption and attract-an-kill using mirid pheromones, (4) identify plant volatiles which attract or repel key beneficial insects, (5) develop formulations with slow-release and rain fastness, (6) to investigate the potential of using Magnet® to enhance refuges for transgenic cotton.This work showed that mirids are nocturnal in their host-finding (response to plant volatiles) and mate-finding (response to pheromone traps) behaviours. Field olfactometer bioassays using fresh lucerne bouquets, hexane washings and synthetic equivalents of volatiles collected from lucerne were done to evaluate potential plant volatiles as attractants or repellents for mirids. Lucerne bouquets were significantly attractive to female mirids but only two chemicals appeared to be attractive and two were repellents to mirids. Combining volatiles into blends did not increase attractiveness to mirids. A technique to improve longevity of mirid pheromone in the field was developed which involved coating the rubber septa with araldite glue but leaving the tip of the septa uncoated. In collaboration with CRC extension officers and researchers, pheromone trapping trials were conducted at 8 locations in NSW and Qld to evaluate the usefulness of pheromone traps for monitoring mirid populations. Results suggested that population dynamics of mirids were different between locations. Pheromone catches were significantly correlated with field mirids at some sites, whilst such correlation was poor at other sites. In some cases, pheromone traps appeared to catch male mirids only when female mirids in the field were mostly mated, suggesting that the effectiveness of pheromone traps might be influenced by the &quote;female competition&quote; effect in the field. Results from this work suggest that pheromone traps on their own may not be reliable monitoring tools, but may be valuable in providing a better understanding of the population dynamics and mirid ecology in general. Mating disruption using mirid pheromones might be feasible provided a method for slow release of pheromone is developed. A regulatory difficulty was encountered with one of the volatile components of the Magnet® formulation and we decided to replace this component with two others, to avoid the need for expensive toxicological research. Many trials of potential alternatives were conducted, and these resulted in the development of a new Magnet® formulation which was at least as attractive as the old one to Helicoverpa spp., and less attractive to beneficial insects. Registration of this new formulation is imminent, and we have conducted trials on its attractiveness on a range of other species in the USA, New Zealand and south east Asia, as well as on applications for improving resistance management for transgenic cotton in Australia.