Although many pathogens and pests have the potential to cause severe diseases and damages to their host plants, plants in nature often appear healthy and are naturally resistant to most pathogens. Nonhost resistance, which describes the ability of a plant species to repel all attempts of a pathogen species to colonize it, represents a major barrier against damaging biotic stressors but remains surprisingly poorly understood due, in part, to a lack of field studies. In their new Spotlight comment titled "Caffeoylputrescine-hexenal-mediated nonhost resistance against leafhoppers", Zhengquin Fu and his collaborators highlight and discuss a recent study from Bai et al. published in Science that identified a volatile compound from tobacco leaves that confers resistance to those leafhoppers. A fascinating study!