Bacterial spot (bacterial leaf spot), caused by the bacterium Xanthomonas cucurbiate (Syn.: Xanthomonas campestris pv. cucurbitae), has become one of the most important diseases of cucurbits, especially pumpkin and winter squash crops. This disease was first reported as bacterial leaf spot on Hubbard squash in New York in 1926. Subsequently, the disease was reported from other cucurbit growing areas in Asia, Australia, Europe, and North America on cucumber, pumpkin, squash, and watermelon. Xanthomonas cucurbitae infects cucumber, gourds, pumpkin, and summer winter squash. The pathogen infects leaves and fruit during the growing season.