Development of a novel acaricide, acynonapyr

Abstract

Acynonapyr is a novel acaricide developed by Nippon Soda Co., Ltd. It contains a unique azabicyclic ring and oxyamine structure and represents the first agricultural chemical that targets calcium-activated potassium channels, classified as Group 33 in the IRAC Mode of Action Classification. Acynonapyr exhibits high selectivity against spider mites across all developmental stages and has minimal impact on beneficial insects and natural enemies, rendering it suitable for Integrated Pest Management systems. The compound acts by inhibiting potassium ion flow through KCa2 channels in spider mites, leading to neurological symptoms such as convulsions and impaired mobility and ultimately resulting in mortality. Electrophysiological studies have demonstrated that acynonapyr effectively blocks Tetranychus urticae calcium-activated potassium channels. Importantly, acynonapyr shows little activity against mammalian calcium-activated potassium channels, contributing to its favorable safety profile. The compound shows efficacy against acaricide-resistant spider mite populations, providing a useful tool for pesticide resistance management.