Aromatic plants in East-Asia to enhance natural enemies towards biological control of insect pests. A review

Introducing flowering plants in fields may attract and benefit predators and parasitoids of insect pests and potentially enhance biological control when associated with crops. Through a vote counting analysis, the present review evaluates whether aromatic plants of East Asia could be used in this purpose. Through a systematic search of the scientific literature, we identified 64 papers published worldwide considering 32 aromatic plant species. We found a significant number of studies reporting that Apiaceae aromatic plants (Anethumgraveolens L., Coriandrumsativum L., Foeniculumvulgare L.) attract and benefit (in terms of longevity and/or fecundity) insect predators. Contrasting results were found for parasitoids, as well as with plant species from other families (mostly Asteraceae and Lamiaceae). Functional traits of plants (corolla shape, colour, volatiles) and of insects (mouthparts mainly) were considered to discuss these results. Additionally, we have not found a significant number of studies reporting an enhancement of biological control in crop or fruit trees cultivated adjacent to aromatic plants. However, the number of studies was limited, suggesting a need for further field-based research. Still, the retrieved studies highlight a recent interest for sowing aromatic plants in fields and orchards towards biological control of insect pests in East Asia and especially in China.