This volume contains the lectures given at the 10th International Congress of Plant Pathology (ICPP 2013) held in Beijing, August 25-30, 2013 on detection and diagnosis of plant pathogens, which represent two fundamental steps in disease management decisions. A quick and reliable detection method in combination with decision support systems is fundamental in order to reduce the damages caused by old and new pathogens, thus permitting to reduce the number of treatments and to contain the potential losses.Molecular methods are available for a number of pathogens and the volume provide good examples of application in different production sectors. Innovative techniques and methods are described to detect and identify different targets: destructive and non-destructive, air- or soil-borne, human- and plant pathogens, in plants or seed-born, native or emerging pathogens, on-site or lab-based. All to support international organizations to secure global trade and agriculture all over the world. This book is aimed at researchers, students in advanced courses and extension services.