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: Deep bark canker
HOST: Walnut
Reddish brown exudate flowing from longitudinal cracks in the trunk. Cankers are deep extending into wood.

Deep bark canker | Walnut
DISEASE: Deep bark canker
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Brenneria rubrifaciens
PATHOGEN SYNONYM: Erwinia rubrifaciens
SOURCE: B. Teviotdale
DISEASE: Deep bark canker
HOST: Walnut
Reddish brown exudate flowing from cracks in trunk, a result of systemic invasion by the bacterium.

Deep bark canker | Walnut
DISEASE: Deep bark canker
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Brenneria rubrifaciens
PATHOGEN SYNONYM: Erwinia rubrifaciens
SOURCE: B. Teviotdale