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Providing evidence to improve practice

Individual study: Implementing of an IPM programme for vegetable brassicas in New Zealand

Published source details

Walker G.P., Cameron P.J. & Berry N.A. (2004) Implementing of an IPM programme for vegetable brassicas in New Zealand. Proceedings of the Fourth International Workshop, 26-29 November 2001, Melbourne, Australia, 365-370.


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Use pesticides only when pests or crop damage reach threshold levels Natural Pest Control

A replicated study in 1998-2001 in Gisborne and Hawke’s Bay, New Zealand (Walker et al. 2004) reported better control of pests by natural enemies when a threshold-based spraying regime was applied compared to conventional regimes. Insecticide use in vegetable Brassica spp. crops was reduced by 40-70% in the second year of the threshold-based spraying programme compared to conventional regimes. The threshold-based regime could potentially save NZ$125/ha when accounting for the cost of monitoring pests and assuming that spraying could be reduced by 3-4 applications/ha. Sprays (using a variety of insecticide types) were timed according to thresholds of diamondback moth Plutella xylostella and aphid (Aphidoidea) infestation, with selective insecticides used in rotation within each year. Details of experimental setup were not provided.