While many Australian cotton growing valleys had the fortune of relatively low Helicoverpa spp. activity during the 1997/98 season, this was not the universal experience. Extremely high pest activity on the Darling Downs has reinforced the concerns that our current over-reliance on insecticides for the management of Helicoverpa on cotton and grain crops is unsustainable. Just as important is the realisation that within the agro ecosystem, action must be taken to attempt to maintain Helicoverpa spp. populations at more manageable levels. While densities of up to 10 eggs per metre can be managed satisfactorily, densities of 50 or more eggs per metre pose serious difficulties, especially if activity persists at this level for several days or even weeks. Helicoverpa spp. populations fluctuate in response to various factors. Where a succession of wild or cultivated hosts are available, successive generations can develop through the spring, summer and autumn months. If progressive population increases take place for whatever reasons, the end result can be serious management difficulties. Such was the case on the Darling Downs during the 1997/98 season, where the earlier than normal appearance of substantial numbers of H armigera and their persistence at high levels throughout the season resulted in high insecticide use and some control difficulties across cotton and grain crops