Plants and herbivorous insects have developed intricate interaction networks through long-term co-evolutionary processes. To counteract herbivory pressure, plants have evolved multi-layered defense mechanisms, while phytophagous insects have correspondingly developed sophisticated counter-defense strategies, resulting in a dynamic "arms race" evolutionary pattern. Microbial communities ubiquitously distributed in the environment, plant tissues and insect systems, which profoundly influence this co-evolutionary trajectory through tripartite "plant-microbe-insect" interactions. These microbial components not only modulate plant defense responses but also significantly affect the environmental adaptability of insects, providing novel perspectives for understanding interspecies interactions. Tuta absoluta, a devastating invasive pest native to South America, poses severe threats to global Solanaceous crop production. In this article, we review the research progress on interactions between T. absoluta and host Solanaceous plant, and the impact of common microorganisms (e.g., insect symbiotic bacteria, soil microorganisms, and pathogenic microorganisms) in farmland ecosystems on the reproduction of T. absoluta populations, plant growth and development, and the regulation of plant defense responses to the T. absoluta. This review has great significance for advancing the understanding of plant-pest interactions.