maladie des raies bactériennes

OBS: Raies bactériennes, Pseudomonas andropogonis. Les premiers symptômes sont de petites (1 cm) taches linéaires entre les nervures. Les taches sur les feuilles et la gaine sont de couleur pourpre, rouge, jaune ou brune, en fonction de la réaction de l'hôte. Si les conditions sont favorables, les taches peuvent dépasser une longueur de 20 cm. On observe de l'exsudat bactérien sur les feuilles infectées.

CONT: Bacterial leaf stripe (Pseudomonas syringae subsp. andropogonis) is widely distributed and destructive on many types of sorghums (grain, forage, and sweet or sorgo), sudangrass, and broomcorn as well as on several other related grasses. Long, narrow stripes (1/4 inch by 9 inches or more) form on the leaves. These stripes are initially water-soaked, irregular, and bounded by veins. These areas soon dry and turn brick red, dark purplish red, reddish brown, or tan-to-dark brown depending on the sorghum variety. The color is continuous throughout the lesion. Later, the stripes elongate and fuse to form irregular blotches that cover a large part of the leaf surface and extend into the leaf sheath. Stalks and floral structures may show similar but more restricted lesions.