Cotyledon Spot of Soybean Caused by Seedborne Curvularia lunata var. aerea in Brazil. J. J. Muchovej, Fitopatologia, Universidade Federal de Višosa, and Satie Kimura, CENTREINAR, 36570 Višosa, MG, Brazil. Plant Dis. 72:268. Accepted for publication 1 November 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0268B.
Among the many seedborne fungi reported to produce necrotic lesions on soybean cotyledons is Curvularia lunata (Wakker) Boedijn. C. I. var aerea (Batista, Lima & Vasconcelos) M. B. Ellis, distinguishable from C. lunata by the formation of upright stroma in vitro on potato-dextrose agar (PDA), has been isolated from surface-sterilized soybean seeds in Minas Gerais, Brazil, on several occasions. Infected seeds show a slight discoloration similiar to that caused by seedborne Colletotrichum dematium (Pers. ex Fr.) Grove. Upon germination, however, the seed coat takes on a reddish tint and the underlying cotyledonary tissues become light brown. Lesions are superficial and irregular in shape and do not enlarge once the cotyledons have expanded. Up to 70% of the surface of infected cotyledons may be affected. Inoculation with PDA-grown three-septate conidia produced the reddish tint and brown spot, and reisolations recovered the pathogen. This is the first report of C.l. var. aerea causing disease on soybean cotyledons. The disease is of minor importance.