PhyLib II is a consortium of 18 institutions from 14 countries that continued the work of the PhyLib consortium. The consortium collaborated on the project: ‘The biology and epidemiology of ‘Candidatus Liberibacter solanacearum’ (Lso) and potato phytoplasmas and their contribution to risk management in potato and other crops (PhyLib II)’. The aims of this project were to expand knowledge of emerging bacterial plant diseases associated with the presence of phytoplasmas and Lso and to survey their distribution, genetic diversity, epidemiology, insect vectors, and risk to crops worldwide. The consortium aimed to co-ordinate research on these crop pests and to provide a network of expertise to develop detection methods and a framework within which to share knowledge and compare the experiences of disease epidemiology across a wide range of geographical locations including North America (Canada), Northern Europe, the Mediterranean basin, Central Europe and Eastern Europe. The consortium developed and validated methods for the extraction of metagenomic DNA and total RNA and for the detection of bacterial DNA from complex matrices including plants, seeds and insect vectors. This involved testing current methodologies and developing novel approaches including High Throughput Sequencing (HTS)-based diagnostic techniques. Through field surveys carried out by the partners, our knowledge of the distribution and genetic diversity of phytoplasmas and Lso worldwide has improved. This includes the discovery of novel Lso haplotypes in different plants and insect vectors and the finding of Lso and phytoplasmas in areas where hitherto they were not known to be present. The consortium was effective in promoting exchange of materials between partners and sharing knowledge, enabling countries to facilitate testing for phytoplasmas and Lso. The consortium will build on the success of PhyLib II and the Euphresco project PhyLib III (17 institutes from 14 countries) has started in 2020.