Long term studies of the ecology of 'Helicoverpa spp' in inland Australia

Since 1987, a group of entomologists from several institutions has been studying the ecology of Helicoverpa spp. (Lepidoptera: Noctuidae) in central Australia. A total of 79 field trips were made to the region, which encompassed inland areas of NSW, Qld, SA, WA and NT. This involved over 2000 sweep net samples for Helicoverpa spp. larvae on over 230 different plant species, mostly natives. It enabled us to develop a comprehensive understanding of when and where Helicoverpa spp. breed on non-crop hosts in the inland, and how they might then migrate to cropping areas. H. punctigera was by far the most common species, with 50.5% of samples yielding larvae. Only 4.2% of samples yielded H. armigera larvae, and these were mostly in the northeast of the study area. H. punctigera larvae were found on 122 plant species from 18 families. Of these, 120 were new host records, though there is doubt about the suitability of some for larval development. Host suitability was assessed using the matrix of Zalucki et al.(1994; Aust. J. Zool. 42, 329), which plots relative incidence against relative abundance.