Abstract BACKGROUND In the context of reducing pesticide use, companion plants (CPs) are a promising method for aphid control, but their effectiveness in field conditions remains inconsistent. This study tested whether applying nitrogen (N) restriction and/or UV‐C flashes to basil could enhance its emission of volatile organic compounds (VOCs) and improve its efficacy against Dysaphis plantaginea (Passerini) and Myzus persicae (Sulzer). RESULTS A 14‐day N restriction significantly increased basil terpene emissions, disrupted D . plantaginea feeding behaviour, and reduced aphid fecundity in both species. UV‐C flashes also transiently boosted VOC emissions 24 h after and slightly affected reproduction. However, combining both treatments had no additive effect. CONCLUSION Lowering N supply appears to be the most effective strategy to increase basil VOCs. Further research should assess its potential when applied simultaneously to companion and host plants in order to improve aphid control. © 2026 Society of Chemical Industry.
Rizzi et al. (Thu,) studied this question.