Cucurbit downy mildew is a devastating disease for the United States cucurbit industry, which includes cucumbers, watermelon, squash, and pumpkin. The disease has caused major losses in North Carolina, which has significant cucumber and watermelon acreage. To help growers better manage this disease, a group of plant pathologists at North Carolina State University sought to better understand the biology of the pathogen that causes downy mildew.