Eclipta prostrata, a New Weed Host for Sclerotinia minor. H. A. Melouk, USDA-ARS and Department of Plant Pathology, Oklahoma State University, Stillwater 74078. J. P. Damicone, and K. E. Jackson. USDA-ARS and Department of Plant Pathology, Oklahoma State University, Stillwater 74078. Plant Dis. 76:101. Accepted for publication 20 September 1991. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0101E.
Eclipta (Eclipta prostrata (L.) L.), a member of the Asteraceae, has become an established weed, infesting about 4,000 ha of irrigated peanut (Arachis hypogaea L.) in Oklahoma. The severity of infestation with this weed as well as Sclerotinia blight, caused by Sclerotinia minor Jagger, on peanut coincides with higher than normal precipitation or frequent irrigation and cool temperatures. S. minor was isolated from blighted eclipta plants in a peanut field with a history of Sclerotinia blight at Stillwater, Oklahoma. Viable sclerotia of S. minor were formed on and in the pith cavity of stems of dead eclipta plants. Detached shoots of eclipta and peanut (cv. Tamnut 74) plants inoculated (1) and incubated for 4 days showed lesions measuring 83 and 81 mm, respectively. About four and eight viable sclerotia per 50 mm of lesion were formed on infected detached shoots of eclipta and peanut, respectively, 15 days after inoculation. These data suggest that eclipta is a potential reservoir for S. minor in field soils in the absence of peanut plants. This is the first report of S. minor on E. prostrata.