Mango (Mangifera indica L.) is one of the highly demanded fruit in Egypt. Mango is susceptible to several diseases at all stages of its development. Among these diseases, is powdery mildew, which caused by the fungus Oidium mangiferae Berthet. It was first reported in Brazil 1914 by Berthet, and subsequently, was reported in several other countries. The losses caused by this pathogen vary from 5-20% depending on the weather conditions. Disease incidence percentage was increased from February (2-5%) until May in the different investigated districts of Sharqia and Ismailia Governorates but with higher values especially during March and April in Ismailia during 2016 and 2017 growing seasons. The highest value of mango powdery mildew disease was obtained during May where it ranged from 43% to 73% when the temperature averaged 26.8°C and relative humidity valued 43.04%. Lengara cultivar proved to be the least affected mango cultivar by the pathogen in season 2016. However, Balady cultivar was highly susceptible and the remained cultivars seemed to be moderately susceptible. All the fungicides screened were found significantly superior in inhibiting the pathogen, O. mangiferae with different degrees and decrease disease incidence and severity rather than non-treated mango trees during seasons 2016 and 2017. Evconel, Apache, Nasr Zool, Super talc, and Bingo significantly decreased disease incidence with equal effects compared to the control. However, fungicide Sopulo displayed the highest disease incidence.Powdery mildew infection was variable among mango cultivars (Naqvi et al., 2014). The use of moderate susceptible cultivars is the http:/www.journals.zu.edu.eg/journalDisplay.aspx?Journalld=1&queryType=Master