Helicoverpa Predators: Do We Know Anything About Them?
Abstract
Insects in cotton fields form a diverse and volatile community. Room (1979) collected some 500 species of insect (plus spiders) in Australian cotton fields. Some (the ones we notice most) are pests. Others are beneficials, that is, predators or parasites of the pests. Room considered more than half of the species he found were predaceous to some extent. However, in most cases, the majority of insects in a cotton field are neither pests nor beneficials. They may feed on cotton, but cause negligible damage (for example, flower beetles and leafhoppers). They may be predators and parasites of these innocuous plant feeders, or of beneficials. They may be soil-dwelling species which rarely enter the foliage. They may feed on nectar or the honeydew produced by aphids and leafhoppers. Finally, they may be just passing through, having arrived accidentally on the wind. All these insects are what we might call "incidental" species - incidental for conventional pest management, but not necessarily in their importance to the pests' ecosystem. Figure 1 summarises the results of sampling on two fields at Auscott's "Midkin" (Moree) property during the 1992/3 season. The numerical dominance of the "incidental" species is plain. Even when pest pressure is high, the numbers of major pests like Helicoverpa spp. are much lower than those of the incidental species.
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- 1994 Australian Cotton Conference
Proceedings from the 1994 Australian Cotton Conference