Plant diseases caused by the pathogenPseudomonas syringaeare serious problems for various plant species worldwide. Accurate detection and diagnosis ofP. syringaeinfections are critical for the effective management of these plant diseases. In this review, we summarize the current methods for the detection and diagnosis ofP. syringae, including traditional techniques such as culture isolation and microscopy, and relatively newer techniques such as PCR and ELISA. It should be noted that each method has its advantages and disadvantages, and the choice of each method depends on the specific requirements, resources of each laboratory, and field settings. We also discuss the future trends in this field, such as the need for more sensitive and specific methods to detect the pathogens at low concentrations and the methods that can be used to diagnoseP. syringaeinfections that are co-existing with other pathogens. Modern technologies such as genomics and proteomics could lead to the development of new methods of highly accurate detection and diagnosis based on the analysis of genetic and protein markers of the pathogens. Furthermore, using machine learning algorithms to analyze large data sets could yield new insights into the biology ofP. syringaeand novel diagnostic strategies. This review could enhance our understanding ofP. syringaeand help foster the development of more effective management techniques of the diseases caused by related pathogens.