Ecological impact of three pest management systems in New Zealand apple orchards

Abstract

Three apple pest-management regimes are being compared for their ecological impacts, and their ability to ensure the economic production of high-quality apples. Species diversity, pest status and fruit quality are being evaluated under: (i) conventional, (ii) integrated, and (iii) biological fruit production systems. The conventional system follows current export orchard practices with broad-spectrum pesticides, and the integrated system uses a wider range of control methods, including minimal spray applications, preferably of selective pesticides. The biological system uses mating disruption for codling moth (at one site), Bacillus thuringiensis for leafrollers, copper/slaked lime for diseases, and matting or mulches for weed control. Conventional production results in few insects being present during the season and little damage at harvest, but increasing insecticide resistance problems and changing market requirements put the sustainability of this system in doubt. In the integrated system, excellent control of Lepidoptera has been achieved using tebufenozide, with little effect on natural enemies. Further development of the system is needed, but the economics appear favourable for producing export-quality fruit in future. In the biological system, the lack of effective controls for key quarantine pests limits economic sustainability and largely restricts production to the local market. The future of this system for export production depends on innovative technology to overcome these problems.