Effective disease management of crops is crucial to sustain food security and safeguard potential losses in crop production that worth billions of dollars. The key to success in plant disease management is having the ability to detect the causal pathogen(s) early and accurately. Polymerase chain reaction (PCR) has been a gold standard in nucleic acid-based diagnostics. Apart from PCR, within the last decade, the development of a technique called "loop-mediated isothermal amplification" or LAMP has facilitated the development of hundreds of simple assays for plant disease diagnostics. There are now more than 200 LAMP publications per year, of which 20% identify plant disease pathogens. Among them, LAMP assays are available for pathogen detection of 50 plant viruses, 20 bacterial plant diseases, 7 fungal plant diseases and several phytoplasmas. Here, we provide a comprehensive analysis of all LAMP assays available for detecting plant diseases, including various detection chemistries used. We also discuss how to avoid pitfalls when developing LAMP assays. Finally, we offer perspectives of the applications of LAMP in plant disease management, addressing the questions as to which extent the assays are helpful and whether they should be used outside the laboratory. This review will be a "handbook" for researchers developing LAMP assays for plant disease diagnostics.