DISEASE: Alfalfa dwarf
HOST: Alfalfa
Alfalfa dwarf is characterized by stunted plants (left), usually dark blue-green in color. Xylem tissues become brown, especially when exposed to air.

Alfalfa dwarf | Alfalfa
DISEASE: Alfalfa dwarf
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Xylella fastidiosa
SOURCE: R. M. Davis
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet
Cross section of sugar beet with reddish color in vascular bundles and adjacent tissues.

Bacterial vascular necrosis and rot | Beet
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet (Beta vulgaris)
PATHOGEN: Pectobacterium betavasculorum
PATHOGEN SYNONYM: Erwinia carotovora subsp. betavasculorum
SOURCE: M. Schroth
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet
Advanced stage of disease with extensive rot.

Bacterial vascular necrosis and rot | Beet
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet (Beta vulgaris)
PATHOGEN: Pectobacterium betavasculorum
PATHOGEN SYNONYM: Erwinia carotovora subsp. betavasculorum
SOURCE: M. Schroth
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet
Early stage of systemic infection of young plant noted by blackening of midribs and veins.

Bacterial vascular necrosis and rot | Beet
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet (Beta vulgaris)
PATHOGEN: Pectobacterium betavasculorum
PATHOGEN SYNONYM: Erwinia carotovora subsp. betavasculorum
SOURCE: M. Schroth
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet
Infected vascular bundles caused by systemic infection by the bacterium.

Bacterial vascular necrosis and rot | Beet
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet (Beta vulgaris)
PATHOGEN: Pectobacterium betavasculorum
PATHOGEN SYNONYM: Erwinia carotovora subsp. betavasculorum
SOURCE: S. Thomson
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet
Black discoloration of petioles resulting from systemic infection.

Bacterial vascular necrosis and rot | Beet
DISEASE: Bacterial vascular necrosis and rot
HOST: Beet (Beta vulgaris)
PATHOGEN: Pectobacterium betavasculorum
PATHOGEN SYNONYM: Erwinia carotovora subsp. betavasculorum
SOURCE: S. Thomson
DISEASE: Syringae leaf spot
HOST: Tomato
Leaves with brown necrotic lesions and chlorotic margins. Symptoms vary greatly among cultivars. Some have black or brown lesions with bright yellow, chlorotic areas and others do not have yellowing.

Syringae leaf spot | Tomato
DISEASE: Syringae leaf spot
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: R. Gitaitis