Queima bacteriana (Xanthomonas campestris) do alho-poró (Allium porrum) em Minas Gerais, Brasil

Abstract

A leek disease found in Vicosa, Minas Gerais, showed pale apical lesions progressing downward from the leaf apex which later became necrotic. These leaves are completely taken up by the infection, dry up and fall off, while the plant remains alive. One bacterium producing medium yellow, shining, regularly edged, elevated colonies was isolated in a standard culture medium. It was unable to induce HR in beans, coffee, passion fruit, tobacco and tomato but induced the same observed leaf symptoms when reinoculated into healthy leek plants. The isolated bacteria are straight, regular, rod-shaped, Gram-negative cells, unable to use asparagine, strict aerobes, xanthomonadin-producers, non tumorogenic and can be positioned in Xanthomonas. Biochemical tests identified X. campestris as the species. The disease may be seed transmitted.