Laboratory and field studies supporting the develo

Authors: S D M Gresham J G Charles M W R Sandanayaka J C Bergh

Publish Date: 2013/06/27

Volume: 58, Issue: 5, Pages: 645-656

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Abstract

Studies supporting a project seeking to introduce Heringia calcarata Loew Diptera Syrphidae to New Zealand NZ to supplement biological control of woolly apple aphid WAA Eriosoma lanigerum Hausmann Hemiptera Aphididae are reported Annual surveys of H calcarata presence and abundance in a Virginia USA apple orchard revealed a bimodal distribution with peaks in midJune and midSeptember In the field female H calcarata oviposited on sentinel apple shoots infested with WAA providing an efficient method for egg collection and larval production Similarly most fieldcollected females readily deposited viable eggs on WAA colonies in laboratory cages demonstrating that mated females will oviposit in captivity Survivorship of eggs and larvae transported to NZ was good yielding adult flies in containment in Auckland Adult virgin female H calcarata reared from eggs in captivity developed mature oocytes providing an important step toward future mating studies in containment Oviposition and larval feeding studies examined aspects of the intraguild interactions between H calcarata and Aphelinus mali Haldeman Hymenoptera Aphelinidae the sole biological control agent of WAA in NZ Field tests using paired sentinel apple shoots with a nonparasitized or parasitized WAA colony revealed that although H calcarata deposited eggs on both parasitized and nonparasitized colonies fewest eggs were deposited on heavily parasitized colonies Feeding studies showed that larval H calcarata consumed fewer mummified aphids or aphids in an earlier stage of parasitization than nonparasitized aphids

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