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Bacterial Sheath Rot of Wheat Caused by Pseudomonas fuscovaginae in the Highlands of Mexico. E. Duveiller, Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Lisboa 27, Apdo. Postal 6-641, Col. Juárez, Deleg. Cuauhtémoc, 06600 México D. F., México. H. Maraite, Laboratoire de Phytopathologie, Université Catholique de Louvain, Place Croix du Sud 2 Bte 3, B-1348 Louvain-la-Neuve, Belgium. Plant Dis. 74:932-935. Accepted for publication 15 February 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0932.

Angular, blackish brown lesions, 10 or 20 cm in length, bordered with a purple-black angular area 1–2 mm wide and showing a grayish center, were frequently observed on leaf sheaths of bread wheat, durum wheat, and triticale at the booting stage in the central highlands of Mexico, 2,249–2,640 m above sea level. Fluorescent, strictly aerobic bacteria identified as Pseudomonas fuscovaginae (based on their positive reaction for Kovac’s oxidase and arginine dihydrolase but negative for esculin hydrolysis and nitrate reduction) were isolated from these lesions. The pathogenic strains from wheat behaved similarly to those isolated from rice in other countries with regard to nonproduction of 2-ketogluconate, acid production from trehalose but not from inositol, agglutination with antiserum against a reference strain, and pathogenicity on rice and wheat.