Phytophthora capsici

Phytophthora capsici is an oomycete plant pathogen that causes blight and fruit rot of peppers and other important commercial crops. It was first described by L. Leonian at the New Mexico State University Agricultural Experiment Station in Las Cruces in 1922 on a crop of chili peppers. In 1967, a study by M. M. Satour and E. E. Butler found 45 species of cultivated plants and weeds susceptible to P. capsici In Greek, Phytophthora capsici means 'plant destroyer of capsicums'. P. capsici has a wide range of hosts including members of the Solanaceae and Cucurbitaceae families as well as Fabaceae. Under field conditions, P. capsici has been found to affect a wide range of hosts in the Cucurbitaceae, Fabaceae, and Solanaceae families, including: cantaloupe, cucumber, watermelon, bell pepper, tomato, snap beans, and lima beans. Although beans, lima beans, and soybeans were previously thought to be immune to P. capsici, in 2000 and 2001, 'Phytophthora capsici was isolated from five commercial cultivars of lima bean in Delaware, Maryland, and New Jersey. It was also recently isolated from commercial snap beans in northern Michigan.' General symptoms on the solanaceous crops and cucurbits include seed rot and seedling blight which discolors the roots and causes seedlings to topple over. Preemergence and postemergence damping-off are also possible symptoms that may occur. Include water-soaked foliage, stem and pod necrosis. Infection of the pepper commonly starts at the soil line leading to symptoms of dark, water soaked areas on the stem. Dark lesions of the stem may girdle the plant resulting in death. Roots of the pepper plant appear brown and mushy. Leaf spots start out small and become water soaked, and as time progresses may enlarge turn tan and crack. Blighting of new leaves may also take place. The fruit of the pepper is infected through the stem giving way to water soaked areas on the fruit that are overgrown by signs of the pathogen which appear as, 'white-gray, cottony, fungal-like growth' (hyphae). The fruit mummifies and stays attached to the stem. Solanum melongena: Fruit rot is the primary symptom of the eggplant. A dark brown area of the fruit expands into a light tan region. Signs of fungal-like growth may be seen on the lesions. Solanum lycopersicum: P. capsici can cause crown infections, leaf spot, and foliar blight in tomato. The plant may eventually topple over from the crown rot. Fruit rot with patterns of concentric rings is another possible symptom.