Scarcity of pesticide data in New Zealand with a focus on neonicotinoids: A review

Abstract

Since Europe's 2018 neonicotinoid ban on outdoor use of clothianidin, imidacloprid, and thiamethoxam, there has been growing political, scientific, and public interest in further understanding the impact of neonicotinoids on bees and the environment. Here, we assessed the trends in pesticide use in New Zealand, with a particular focus on neonicotinoids, to aid discussion on their use and associated risks. Obtaining data on annual trends in pesticide quantities is challenging, as there is no central collection of pesticide data across the agrichemical or regulatory sectors in New Zealand. Consequently, the true scale and frequency of pesticide usage, including neonicotinoids, remain largely unknown. The difference in neonicotinoid use patterns between New Zealand, where 45 % of forage brassicas (annual planting) and pastures (infrequent planting) are grown from neonicotinoid-treated seeds, and northern hemisphere countries, where 56 % to over 90 % of annual food crops rely on neonicotinoid-treated seeds, indicates a lower overall neonicotinoid use in New Zealand. This difference underscores the need for region-specific approaches to pesticide management and regulation. Although residues can persist and migrate in the soil, current regulations only consider the risk of foliar spray to protect honey bees, overlooking the potential risks to native bees, which primarily live underground, as well as wider lethal and sublethal impacts of residues on non-target organisms. The lack of publicly accessible pesticide data limits scientific research on non-target and environmental effects, and the absence of readily available substitutes for neonicotinoids is the key challenge to be overcome in order to better manage the impact of these pesticides on New Zealand ecosystems.