The “Preference-Performance Hypothesis” predicts that female moths oviposit on plants that are the most suitable for their progeny. In this context, herbivore-induced changes in plant volatiles can serve as cues guiding oviposition decisions. We investigated this paradigm in the diamondback moth, Plutella xylostella, by characterizing herbivory-induced changes in the volatile bouquet of Arabidopsis thaliana and testing how these changes influence both female oviposition preference and larval performance. We found that both mechanical damage and infestation by Plutella xylostella larvae induced the release of erucin, a glucosinolate-derived isothiocyanate. In parallel, P. xylostella females preferentially oviposited on previously infested plants over healthy controls. Using myb28myb29 mutant plants, impaired in aliphatic glucosinolate biosynthesis, abolished female preference for damaged plants. Conversely, supplementing healthy WT and myb28myb29 plants with synthetic erucin restored oviposition preference. Despite this attraction, larval performance was reduced on both previously infested and erucin-supplemented plants, though adult emergence was not affected. These results suggest that erucin acts as a volatile cue shaping oviposition decisions in P. xylostella, but may lead to a mismatch between female preference and offspring performance.