Diseases caused by plant pathogens (fungi, bacteria, viruses and viroids, as well as abiotic stresses) cause losses ranging from 5 to 50%, in different geographic areas. Plant protection, despite the availability of sophisticated technologies, is complicated by several factors. Climate change, by shifting crops and pathogens, and global trade, by moving goods, including seeds and planting material, have a strong influence on the spread of new and old pathogens. Smart technologies (diagnostic tools, sensors, long distance monitoring, …) help in the process of reducing external inputs, such as pesticides. A number of practical examples will be presented and critically discussed.