The primary objective of this study is to investigate the selective pressures and defensive hurdles that the polyphagous pest Tetranychus urticae encounters when colonizing citrus hosts. We aim to identify how endogenous resistance mechanisms—expressed through secondary metabolites in the rhizosphere and phyllosphere—are fundamentally altered by Arbuscular Mycorrhizal Fungi (AMF). Furthermore, the study seeks to decode the «chemotypes» involved in inter-plant communication to understand how the symbiosis affects the "alarm" signals that trigger defensive responses in neighboring plants. The study utilized citrus plants to evaluate species-specific defensive responses against T. urticae herbivory. We analyzed the production of endogenous secondary metabolites released into both the soil and the air. To assess the impact of multitrophic interactions, plants were inoculated with AMF to establish a functional symbiosis. We specifically monitored the chemical signaling between mite-infested «donor» plants and neighboring «receiver» plants, measuring the resulting alterations in the receivers’ chemical profiles and the subsequent impact on mite fitness, including reproductive success and feeding behavior. Our findings indicate that the symbiosis between citrus and AMF significantly enhances the plant’s defensive resposne, creating a more hostile environment for the mite. Crucially, this fungal association acts as a biochemical modulator, altering the composition of the chemical language used in inter-plant signaling. This interaction leads to a priming effect; when in symbiosis with AMF, the plant response is markedly boosted, allowing neighboring plants to perceive and «decode» signals more effectively. This enhanced priming of systemic resistance occurs before the first mite even arrives, directly suppressing T. urticae performance. We demonstrate that these species-specific signals are transformed by the symbiont, increasing the efficacy of the «alarm» received by the plant community. This may be an indicative that primed immunity can be also transferred from plant to plant. By deciphering how T. urticae herbivory serves as the initial trigger for these complex multitrophic networks, we provide new insights into the mite’s ecological niche and its management. Understanding the intersection of symbiotic fungi and inter-plant signaling provides a new frontier for Integrated Pest Management (IPM). Ultimately, these results allow for the development of robust, biologically-driven strategies to protect citrus orchards by leveraging the plant’s own communication channels and the priming power of AMF to suppress mite populations.