• Research in Plant Disease
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• v.11 no.2
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• pp.146-151
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• 2005

A new bacterial disease of sesame(Sesamum indicum) was observed on field-grown plants in Suwon, Hongchun and Yeonchun in 2000. Leaf symptoms initially appeared as water-soaked spots that gradually enlarged, became necrotic and were often bordered by a small zone of lemon yellow tissue. In the case of severe infection, dead leaves were defoliated. Isolations made from diseased leaves on yeast extract dextrose calcium carbonate agar yielded nearly pure cultures of a yellow-pigmented bacterium typical of a xanthomonad. Two bacterial strains were purified and used for farther tests. Pathogenicity of strains was confirmed on 3-week-old sesame plants sprayed with bacterial suspensions containing $10^{8}cfu/ml$ of phosphate buffered saline. The Biolog and fatty acid analyses of the two strains(SL3451 and SL3476) 1mm sesame leaf blight showed that they could be identified as ft campestris pv. sesami because of their high similarity to the tester strain(X. campestris pv. sesami LMG865) with a match probability of $100\%$. The bacterium grew well between 18 and 36$^{\circ}C$, but optimum temperature was $27^{\circ}C$ on LB broth. This is the first report of bacterial blight of sesame in Korea. Symptoms of bacterial blight of sesame are difficult to differentiated with those of bacterial leaf spot caused by Pseudomonas syringae pv. sesami.