A foundational concept in plant-microbe interactions, known as the Disease Triangle, states that the host, the pathogen and the environment all contribute to observed disease severity. While many molecular mechanisms have been described for the interaction between hosts and pathogens, placing these interactions in the context of a variable and complicated environment has been more challenging. Xanthomonas is a known pathogen of most crop plants. As a culturable, genetically tractable bacterium with a small genome, Xanthomonas is also an excellent model for studying the disease triangle. Distinct yet complementary projects of cassava, cotton and sorghum will be discussed including: (1) use of transcriptomics to simultaneously monitor molecular changes in host and pathogen, (2) forays into phenomics to elucidate the role of the environment on disease progression and (3) efforts to translate discoveries into impactful crop improvement.