A Pictorial Series of Disease Assessment Keys for Bacterial Leaf Streak of Cereals. E. DUVEILLER, Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Lisboa 27, Apdo Postal 6-641, Col. Juarez, Del. Cuauhtemoc, 06600 Mexico D.F., Mexico. Plant Dis. 78:137-141. Accepted for publication 20 September 1993. 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0137.

A series of disease assessment keys based on the percent affected leaf area at flowering stage is proposed as a tool to better evaluate bacterial leaf streak symptoms in barley, bread wheat, durum wheat, triticale, and rye. Streak symptoms are more distinct in barley, triticale, and rye than in wheat. The series of standard area diagrams is based on disease patterns on leaves from naturally infected fields and shows that symptoms progress from the central part of the leaf, where free water remains longer in the morning, and not only from the tips of the leaves downward, as suggested previously. Also, the study of bread wheat genotypes that vary in resistance to bacterial leaf streak indicates that stripes are a bit more conspicuous in susceptible genotypes than in resistant ones.

Keyword(s): black chaff, disease scales, Xanthomonas campestris pv. translueens, X. c. undulosa