Insect herbivore induced above-and belowground plant communication: ecological and applied aspects

Plants have evolved complex defence strategies against herbivores, including direct and indirect defences mediated by phytohormonal cascades. These defences can be induced by herbivore attack, by root symbionts or by the perception of volatile organic compounds (VOCs) emitted by neighbouring plants or microbes. Accordingly, we review how aboveground, plants release VOCs that serve as semiochemicals for inter- and intraspecific communication, attracting herbivores or their natural enemies. Furthermore, we discuss how belowground, plants communicate through root exudates, which can trigger neighbouring plants to emit volatiles and enhance biological pest control. Efforts to particularly harness belowground plant communication for sustainable crop protection include utilizing root exudates to inhibit weed germination, attract pest antagonists, and enhance beneficial microbe associations. Yet, further research is needed to uncover the full potential of belowground plant communication in increasing crop yield and shaping ecosystem dynamics. Understanding the context-dependency of plant responses to semiochemicals will be crucial for optimizing management strategies and ensuring food security in the face of evolving pest pressures.