Disease Note.

First Report of Fusarium Leaf Blotch of Rice. N. Iboton Singh, Department of Plant Pathology, College of Agriculture, Central Agricultural University, Iroisemba, Imphal-795 001, India. R. K. Tombisana Devi, Department of Plant Pathology, College of Agriculture, Central Agricultural University, Iroisemba, Imphal-795 001, India. Plant Dis. 79:1186. Accepted for publication 19 July 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-1186A.

During October of 1992 and 1993, a severe leaf blotch disease on rice was observed in the experimental fields of the College of Agriculture, Central Agricultural University, Imphal, and several hectares of farmers' fields in valley areas of Manipur. The disease incidence ranged from 50 to 70% with 25 to 40% reduction in grain yield. Symptoms consisted of irregular, oblong, brown, necrotic areas, 5 to 6 x 14 to 20 cm, with water-soaked margins that eventually coalesced, resulting in blight of the leaf blade. The disease usually first appeared a few contimeters from the leaf tip during the boot stage of rice or later. Surface-disinfested leaf tissue plated on potato-dextrose agar (PDA) yielded Fusarium solani (Mart.) Sacc. Pathogenicity of the fungus was demonstrated on rice plants by incubating plants in perforated polyethylene bags after spraying plants with fungal fragments prepared from 7-day-old culture. Forty-eight hours after inoculation, all 15 rice plants showed blotch symptoms characteristic of naturally infected rice plants. Necrotic leaf tissue from artificially inoculated plants was plated on PDA and consistently yielded F. solani. The identity of the fungus was confirmed by the International Mycological Institute (IMI 342485). This is the first published report of a Fusarium leaf blotch of rice.