Intercropping with aromatic plants enhances natural enemy communities facilitating pest suppression in tea plantations

Habitat management have received considerable attention in agricultural systems for the promotion of successful pest management. The intercropping of aromatic plants in plantation crops can result in reduced pest abundance as a repellent directly and/or increasing natural enemy abundance thereby reducing pest abundance indirectly. To promote the management of pests in tea plantations, we intercropped three aromatic plants, Tagetes patula (L.) (Asteraceae), Tagetes erecta (L.) (Asteraceae), and Perilla frutescens (L.) Britton (Lamiaceae) to assess their impact on the dynamics of species abundance, richness, and diversity of arthropod pests and their natural enemies over 2 years. Results showed that aromatic plants decreased the abundance of pest, with concomitant increases in predator (especially spiders and ladybirds) and parasitoid (Ichneumonidae spp.) abundance, creating a stable low abundance of pests in tea plantations. The ratio of natural enemies to pests in fields intercropped with T. erecta was fourfold to sevenfold higher than observed in naturally tilled plots. Aromatic plants also had a significant positive effect on species richness and evenness of natural enemies. The T. patula and T. erecta intercropped treatments showed significantly higher pest evenness and higher natural enemy diversity than that in clean tillage. Our study indicated that biocontrol via habitat management with intercropping aromatic plants could become a recommended practice for pest management in tea plantations.