Selected orchard practices were evaluated for their influence on powdery mildew infections (caused by Podosphaera clandestina) of sweet cherry in two orchards in Oregon. Three training systems (Spanish bush, steep leader, and central leader), four rootstocks (Edabriz, Maxma 14, Mazzard, Pontaleb), and five cultivars (cvs. Bing, Lapins, Regina, Staccato, and Sweetheart) were included in our studies. Mildew severity was significantly the highest on trees trained on the Spanish bush system (10.7% and 16.6% of leaf surface colonized in 2003 and 2004, respectively) when compared with Vogel central leader (2.7% and 10.8% of leaf surface colonized in 2003 and 2004, respectively) and steep leader (5.3% and 6.9% of leaf surface colonized in 2003 and 2004, respectively) systems. Foliar mildew infections were significantly the lowest on rootstock Edabriz (0.5% and 1.5% of leaf surface colonized in 2003 and 2004, respectively). A range of susceptibilities was noted among the cultivars tested. Cv. Regina had the lowest level of foliar mildew infections in both 2003 and 2004 (0.1% and 0% of leaf surface colonized, respectively), whereas cvs. Staccato and Sweetheart had the highest (32.6% and 33.4% of leaf surface colonized, respectively). Results indicate that selection of training system, rootstock, and cultivar may impact the severity of powdery mildew infestations in sweet cherry orchards.