Volatile‐mediated defence induction in potato plants: transient suppression of Myzus persicae and enhanced recruitment of Harmonia axyridis and Aphidius gifuensis

BACKGROUND: When plants are attacked by herbivores, they release a distinct blend of herbivore-induced plant volatiles (HIPVs) that prime or induce defence in neighbouring plants, enhancing defensive capabilities. Although HIPVs mediate tritrophic interactions, the temporal dynamics of aphid-induced volatile effects remain insufficiently explored. Our hypothesis was that HIPVs emitted by aphid-infested plants could affect neighbouring plants, leading to reduced aphid performance and greater attraction of natural enemies. RESULTS: Using a controlled unidirectional airflow system, receiver potato plants (Solanum tuberosum) underwent 48 h of exposure to volatiles released by either aphid-infested or uninfested conspecifics. Bioassays with Myzus persicae and its natural enemies (Harmonia axyridis, Aphidius gifuensis) were conducted at two time points: during the period immediately following exposure (time point 1: 0-48 h post exposure) and during a subsequent period (time point 2: 48-96 h post exposure). At time point 1, aphid survival and neonate production significantly decreased on HIPV-exposed plants versus controls, although settlement was unaffected. Both natural enemies exhibited significant attraction to HIPV-exposed plants. Volatile analysis of the receiver plants after the exposure period revealed significantly elevated total emissions, with seven individual compounds showing higher levels. At time point 2, insect responses showed no significant differences. However, the volatile profile shifted: some compounds elevated at time point 1 were not sustained, although a distinct set of six compounds remained significantly elevated. CONCLUSION: Brief exposure to aphid-induced HIPVs triggers rapid, transient induction of indirect defences in neighbouring plants. This creates a time-limited window immediately after exposure (0-48 h post exposure) during which aphid performance is reduced and attraction of natural enemies is enhanced, aligning with a difference in volatile profile compared with that observed 48 h later (48-96 h post exposure). Our findings highlight the ecological relevance of volatile-mediated plant communication and its potential for temporally precise defence induction in neighbouring plants. © 2026 Society of Chemical Industry.