The beetle genus Agrilus has over 3000 species which makes it the most numerous in the Animal Kingdom. Many species are serious pests of plants with high invasive potential. Among them, the notoriously known Agrilus planipennis invaded from Asia to North America where it killed tens of millions of ash trees, caused regulatory agencies to enforce quarantines and cost municipalities, property owners, nursery operators and forest products industries tens of millions of dollars. The monograph provides coherent, comprehensive and critical review on all known host plants for more than 680 Agrilus species. All host plants have assigned the confidence index from 0-3 based on the evaluated reliability which eliminates false records. All original and subsequent references for particular plants are cited at each Agrilus species. Data are organized from both, insect and plant viewpoints. Results are analyzed and illustrated by graphs and diagrams. The main impact of the monograph is seen in entomology, phytopathology, forestry, agriculture ecology and biocontrol.