Thirty years of Helicoverpa research in inland Australia: Part 1- The insects and their hosts

AROUND the world, semi-arid regions with unpredictable rainfall are outbreak areas for certain insect pests. The locusts and armyworms of Africa are classic examples, as are our own Australian Plague Locusts. These insects are highly polyphagous (they can utilise many plant species) and highly migratory. They have short life cycles and lay many eggs, meaning they can reproduce very quickly. Ecologists call this set of characteristics the r-strategy, and it works by enabling insects to colonise areas that have recently become favourable, where their population growth is largely free of constraints from natural enemies. Many agricultural pests are r-strategists, and in the 1980s a group of entomologists realised that Helicoverpa (then the number one enemy of conventional cotton) fitted the model. The Helicoverpa Inland Research Group (HIRG) was formed by researchers from the University ot New England, CSIRO, Queensland DP/ and the University of Queensland, and for seven years we studied the distribution and abundance of Helicoverpa in a broad region of inland Australia, with funding from CRDC, GRDC and RIRDC.