Rhubarb (Rheum rhabararum, R. officinale, and R. palmatum) belongs to the Buckwheat family. As an herbaceous perennial, it has been used for medicinal purposes in Asia since 270 BC. As a vegetable, it is grown for its large fleshy edible stalks; the leaves are very toxic. Although clearly a vegetable, rhubarb is prepared and eaten more like a dessert fruit most commonly in pies. The plant became popular in North America around the 1800s. Today cultivation in the USA is less than 1500 acres with Michigan, Oregon, and Washington having the largest acreage. The plant requires cool temperatures to induce stalk emergence. Today most cultivars are hybridized between Rheum species so Rheum x hybridium is generally more accurate. R. officinale, R. palmatum, R. rhaponticum, and R. undulatum are also species names given to rhubarb. Therefore, the seed rarely breeds true requiring the crop to be propagated asexually. Crowns are planted in the spring or fall and harvested 1–2 years later in early spring making it the first vegetable to be harvested in cooler regions. Due to the relatively low acreage of rhubarb globally, detailed strategies for disease management have not been developed for most diseases. Only a few diseases attacking rhubarb have been viewed as limiting and are presented below. These include rhubarb leaf and petiole spot disease, downy mildew, Botrytis blight, Phytophthora crown rot, and red leaf disease.