Spatial Distribution and Mortality of Helicoverpa spp. Pupae (Lepidoptera: Noctuidae) under Field Crops on the Darling Downs, Queensland

Abstract

The spatial distribution and mortality of Helicoverpa punctigera (Wallengren) and H. armigera (Hübner) pupae were investigated under field crops on the Darling Downs, Queensland. Mean pupal depth was 47.3 mm for H. punctigera and 46.2 mm for H. armigera. For each species, the mean depth of male pupae was significantly greater than that of female pupae. In rain‐grown crops where distinct ridges were not formed for the plant rows, pupae were evenly distributed across the inter‐row space. Average pupal survival was 36.6% (range 11.8–70.2). Parasitism averaged 37.0% (range 8.2–61.9). Seven primary parasitoids and four hyperparasitoids were recorded from pupae. Predation by Agrypnus sp. larvae was recorded under sorghum. More intensive sampling of non‐diapausing, overwintering and spring diapausing pupal populations are warranted to further investigate mortality factors. Copyright © 1994, Wiley Blackwell. All rights reserved