Knowledge of the recent distribution, host range, virulence, DNA profiles, and resistance to fungicides of Pseudoperonospora cubensis (Berk. & M. A. Curtis) Rostovzev, and sources of host resistance to this pathogen are reviewed (Lebeda and Cohen, 2011; 2012; Cohen et al., 2015). P. cubensis is widely distributed in all continents, with a high capacity to adapt to changing environmental conditions and new regions. Its host-plant range includes more than 60 species and 20 genera of Cucurbitaceae (Lebeda and Schwinn, 1994; Lebeda and Cohen, 2011). P. cubensis exhibits clear host specialization, with shifts in host range and an increasing spectrum of new host species (Lebeda et al., 2011).