Peppermint interplanting and nitrogen fertilisation for green peach aphid management in peach orchards: Field evidence of VOC-mediated effects

Abstract

A potential strategy for reducing pesticide applications within a cropping system is the use of agroecological practices to alter pest behaviour. Among these practices are the use of companion plant and the management of nitrogen fertilisation. Companion plants (CPs) emit volatile organic compounds (VOCs) that can influence aphid behaviour. Nitrogen fertilisation may affect aphid feeding and, consequently, aphid population growth, as it alters plant composition and development. The objective of this study was to determine whether the combination of nitrogen fertilisation and Mentha × piperita ground cover could modify the incidence of Myzus persicae in a peach orchard. We conducted a factorial experiment quantifying M. persicae incidence, VOC emissions, Prunus persica growth, and agronomic performance under contrasting nitrogen levels, with or without Mentha × piperita cover. This study provides field evidence of peppermint VOC production. We identified specific volatile compounds around peach trees associated with peppermint, including menthone, menthyl acetate, and eucalyptol. A high nitrogen level increased peppermint VOC emissions, reduced M. persicae incidence, and enhanced peach tree growth. The peppermint cover appeared to slightly improve the visual appearance of fruits at harvest. Fruits quality remained within commercial standards in terms of sugar content and overall yield, and fruit size was not significantly reduced despite potential resource competition with peppermint. Further research is needed to better understand the specific factors influencing VOC emissions and their effects on aphids at a finer temporal scale.