Crop plants interact with both arthropods and microorganisms, including pests that reduce yields (in Europe up to 20% annually) and mutualists that promote yield. Direct and indirect interactions between microorganisms and arthropods on crops can strongly modify their impacts on yield. For instance, herbivores and pathogens can facilitate each other, causing additional yield loss. On the other hand, beneficial microorganisms can induce defenses that protect plants against herbivores. There is thus potential to enhance crop production and reduce pesticide use if we can better predict and manage Crop-Arthropod-Microorganism (CAMo) interactions to our advantage. Currently, knowledge of CAMo interactions is limited due to historical separation of the involved research fields. This COST Action will therefore combine existing expertise on CAMo interactions in Europe, from basic and strategic research to agri-R&D companies, and form an interdisciplinary platform and incubator for research on mechanisms, impacts and utilization of CAMo interactions on crop yield. The COST Action will also strengthen the careers of both female and young researchers, connect the newest research in the field with its applied use, and develop new monitoring and management support systems and CAMo-based applications.