Trends in agrichemical use on stonefruit orchards in New Zealand from 2004–2019

Abstract

ABSTRACT Annual spray diaries from orchardists in the two main stonefruit growing regions, Central Otago and Hawke’s Bay, were analysed. The analysis was restricted to products for disease and arthropod pest control. It included apricots, cherries, nectarines, peaches and plums grown as fresh fruit for export and domestic markets, and processing crops. Mean fungicide and bactericide applications declined from 13 to 9/block/year in Central Otago, but rose from 11 to 13 sprays in Hawke’s Bay. Central Otago is drier than Hawke’s Bay and the regional spray programmes now better match the respective climates. Despite large annual variations in rainfall and numbers of brown rot (Monilinia fructicola) infection periods in both regions, there was little correlation with the numbers of fungicides applied that had activity against brown rot. The products used against diseases changed substantially during the study period. Insecticide and miticide sprays averaged 5 applications per year in Central Otago at the start of the study and declined to 4-6/crop/year (overall mean of 4) by 2018–19. Hawke’s Bay growers used 1–3 insecticide sprays per crop (overall mean of 2) throughout the study. The proportion of selective insecticides applied grew in Central Otago, but fell in Hawke’s Bay.