The wheat curl mite (WCM, Aceria tosichella) is the vector of several globally important cereal viruses. However, WCM populations are genetically structured, and major mitochondrial lineages such as MT-1 and MT-8 differ in traits relevant to epidemiology, including host use, invasiveness, and vector competence. In Australia, the epidemiology of WCM-transmitted viruses is still not well understood, despite the presence of wheat streak mosaic virus (WSMV, Tritimovirus tritici) and High Plains wheat mosaic emaravirus (HPWMoV, Emaravirus tritici) in cereal systems. Current management strategies are still shaped largely by studies from the U.S. Great Plains, while major gaps remain in our understanding of how these viruses interact with mites and how they are transmitted. This presentation will provide a brief overview of current knowledge of the WCM-virus complex and highlight the main knowledge gaps. It will also present results from our study on WSMV accumulation in two major WCM lineages, MT-1 and MT-8. Using direct RT-qPCR we compared virus titers in immature mites after feeding on infected wheat and throughout development to the adult stage by quantifying viral loads in individual mites. We also related these patterns to known differences in transmission efficiency between MT-1 and MT-8. Our study was designed to test whether lineage-specific vector competence is linked to differences in virus uptake, retention, and possible replication, with particular attention to virus titers at different mite developmental stages. Comparative analyses of MT-1 and MT-8 suggest that differences in virus accumulation could be linked to contrasting transmission outcomes. These findings also help to explain why some WCM lineages play a bigger role in cereal virus epidemiology than others. Overall, this work highlights the need for further studies on mite-virus interactions and for closer integration of vector biology into cereal virus epidemiology. Understanding how WSMV is acquired, retained, and transmitted by different WCM lineages is essential for improving surveillance, resistance breeding, and management strategies in Australia and elsewhere.