Mungbean (Vigna radiata) is the most widely grown summer legume crop in Australia, with an annual production of approximately 100,000 tonnes across Queensland and northern New South Wales. Powdery mildew is a common disease of mungbean caused by two species, Podosphaera xanthii and Erysiphe vignae. Recent field trials indicated that the disease may cause up to 40% grain yield losses if epidemics start before flowering, environmental conditions are conducive to the disease, and infections are left unmanaged. Commercial mungbean varieties are similarly affected by the disease due to limited genetic resistance. Therefore, if symptoms are present in the canopy and the conditions are conducive, the only management option is to use fungicides. Two mode-of-action (MoA) groups, quinone outside inhibitors (QoI, Group 11) and demethylation inhibitors (DMI, Group 3), are currently registered for mungbean powdery mildew management. However, DNA mutations associated with both QoI and DMI resistance, G143A and G461S, respectively, have been detected in P. xanthii populations in the Darling Downs region in Queensland. The G143A mutation has also been detected in the E. vignae populations. Approaches to quantify each species and the frequency of fungicide-resistant and sensitive alleles in field samples can provide valuable information for managing fungicide resistance risk and disease. This project has developed species-specific quantitative PCR (qPCR) assays to distinguish the two powdery mildew pathogens, P. xanthii and E. vignae. Allele-specific qPCR assays are currently under development to detect and quantify fungicide-sensitive and resistant allele frequencies in powdery mildew field samples. The optimised and validated PCR tests will demonstrate the current field situation for fungicide resistance and the risk of maintaining fungicide-based approaches for disease control. This information aims to support informed decisions for fungicide management of mungbean powdery mildew and contribute to the sustainable use of the available fungicide MoA groups.