First Report of Stem and Fruit Rot of Pepper Caused by Sclerotinia sclerotiorum in Ohio. Y. Yanar, Department of Plant Pathology, The Ohio State University, OARDC, Wooster 44691. F. Sahin, and S. A. Miller, Department of Plant Pathology, The Ohio State University, OARDC, Wooster 44691. Plant Dis. 80:342. Accepted for publication 11 January 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-0342C.
Sclerotinia stem and fruit rot, also called pink-joint, caused by Sclerotinia sclerotiorum (Lib.) de Bary, has been considered a disease of minor importance on pepper (Capsicum annuum L.). However, incidence of the disease has increased in Ohio in recent years, causing economic loss especially in the northwest part of the state where peppers are grown in rotation with soybeans. Unlike white mold of bean and soybean, disease symptoms have been observed in both mature and seedling pepper plants in the field. The disease was first observed in southwest Ohio (Gallia County) in June 1992. Incidence of stem rot in pepper seedlings ranged from 10 to 20% in the affected field 10 days after transplanting. In August 1992, an estimated 30 to 40% loss due to stem and fruit rot was observed in a 20-acre processing pepper field in Henry County (northwest Ohio). The principal symptom on pepper seedlings is a lesion that encircles the stem, usually beginning 5 to 7 cm above the soil line, often extending to the top of the seedling. Affected plants usually wilt and die. On mature plants, light brown water-soaked lesions develop on main stems and branches. White fluffy mycelia develop on infected tissue, and black sclerotia develop externally among the white mycelia and internally in the stem. Lesions usually dry, appearing bleached and light tan in color, and affected steins become hollow. Fruit infections begin as water-soaked, dull green spots that expand rapidly to encompass the entire fruit. Superficial cottony mycelia develop inside the fruit, and black, round to irregular or oblong sclerotia form in the mycelial mat. Sclerotinia sclerotiorum was isolated from bell pepper seedlings collected from commercial fields in Gallia County in June 1992, Sandusky County in June 1994, and Huron and Wayne counties in May 1995. The pathogen was also isolated from mature pepper plants in Henry County in August 1992, Fulton County in July 1994, and Huron County in August 1995. Pathogenicity of 5. sclerotiorum isolates was demonstrated by artificial stem inoculation of 8-week-old pepper plants (var. Marengo) with mycelia grown on autoclaved toothpicks. Koch's postulates were satisfied after reisolating the fungus from infected plants onto potato dextrose agar. Sclerotinia stem rot of pepper has been reported in Florida, Iowa, Texas, Massachusetts, and Connecticut, but this is the first report of the disease on pepper in Ohio.