Pasture management to control Australian soldier fly

Abstract

In New Zealand, the Australian soldier fly, Inopus rubriceps (Macquart) has two peaks of emergence and egg laying per year. The eggs are laid into pasture during late spring (November-December) and autumn (March-April) and close grazing of the sward at these times limits the recruitment of new larvae into the soil populations. Hard grazing (taking pasture to 500 kgha:' DM standing) at the peaks of flights resulted in an estimated 75-80% control of soldier fly larvae when applied for 5 consecutive flight seasons (2.5 years). Grazing of moderate intensity (to 1000-1500 kg ha' DM) reduced population densities by 45-60% over the same period. The effects of close grazing on soldier fly densities were cumulative. One grazing in the week of peak flights was found to be as effective as up to four separate grazings over the extended pupation, emergence, flight, and egg laying periods. The effect of close grazing was to create unfavourable soil microclimatic conditions for egg survival in particular.