Previous View
 
APSnet Home
 
Plant Disease Home


Disease Note

A New Leaf Spot of Sorghum Caused by Cochliobolus bicolor in Tamil Nadu, India. P. Lakshmanan, Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore 641003, India. L. Mohan, S. Mohan, and R. Jeyarajan. Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore 641003, India. Plant Dis. 71:651. Accepted for publication 11 March 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0651B.

During August 1985 and 1986, a previously undescribed leaf spot was observed on the grain sorghum (Sorghum bicolor (L.) Moench) cultivar KS 6312. Lesions were circular with alternating concentric, straw colored bands and, in severe cases, coalesced on a large proportion of the leaf surface. The pathogen was isolated and identified as Cochliobolus bicolor Paul & Parberry (Herb. IMI No. 303555). Pathogenicity was tested by spraying a conidial suspension (107/ ml) on 48-day-old KS 6312 plants. Ten inoculated plants were covered with plastic bags for 24 hr. Typical zonation occurred 10 days after inoculation. The pathogen is reported to cause zonate leaf spot on Pennisetum cladestinum Hochst. ex Chiov. in Brazil (1). This is the first report of C. bicolor causing leaf spot on S. bicolor.

Reference: (1) J. J. Muchovej. Plant Dis. 64:1035, 1980.