The entire range of crops referred to as cucurbits are affected by various foliar diseases in the Northeast. Most damage appears on leaves and stems, but in several instances the fruit are directly infected or will develop poorly if foliar infections are severe. The diseases discussed are angular leaf spot, caused by the bacterium Pseudomonas syringae pv. /achrymans, and three fungal diseases: Ulocladium leaf spot caused by Ulocladium cucurbitae, which only infects cucumber; Alternaria leaf blight caused by Alternaria cucumerina, which potentially can infect all cucurbits but is most important on cantaloupe and muskmelon; and downy mildew caused by Pseudoperonospora cubensis, which can be important for all cucurbits when weather conditions are favorable.