DISEASE: Bacterial blight
HOST: Hazelnut
Diseased young tree with discoloration of the cambium. Dieback of young twigs and branches is characteristic. Other typical symptoms are bud and twig necrosis and small, angular or round, water-soaked leaf spots.

Bacterial blight | Hazelnut
DISEASE: Bacterial blight
HOST: Hazelnut (Corylus americana)
PATHOGEN: Xanthomonas arboricola pv. corylina
SOURCE: J. Pscheidt
DISEASE: Bacterial wilt
HOST: Alfalfa
Longitudinal section of defined brown gum pockets on inner surface of root bark.

Bacterial wilt | Alfalfa
DISEASE: Bacterial wilt
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Clavibacter michiganensis subsp. insidiosus
SOURCE: S. Thomson
DISEASE: Bacterial wilt
HOST: Alfalfa
Infected plant (left) with typical symptoms of stunting and chlorosis. Other characteristic symptoms are spindly stems and small distorted leaflets. Healthy plant (right).

Bacterial wilt | Alfalfa
DISEASE: Bacterial wilt
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Clavibacter michiganensis subsp. insidiosus
SOURCE: S. Thomson
DISEASE: Bacterial wilt
HOST: Alfalfa
Diseased plant with chlorotic leaves.

Bacterial wilt | Alfalfa
DISEASE: Bacterial wilt
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Clavibacter michiganensis subsp. insidiosus
SOURCE: S. Thomson
DISEASE: Bacterial wilt
HOST: Alfalfa
Cross sections of diseased roots with defined brown gum pockets on inner surface of bark. Healthy root (upper left). Other sections represent increases in disease severity.

Bacterial wilt | Alfalfa
DISEASE: Bacterial wilt
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Clavibacter michiganensis subsp. insidiosus
SOURCE: L. Claflin
DISEASE: Pith necrosis
HOST: Geranium
Geranium with wilted, yellow necrotic leaves.

Pith necrosis | Geranium
DISEASE: Pith necrosis
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Pseudomonas corrugata
SOURCE: A. Magyarosy, D. Thomas
DISEASE: Pith necrosis
HOST: Geranium
Pitted and hollow stems, one of the disease symptoms.

Pith necrosis | Geranium
DISEASE: Pith necrosis
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Pseudomonas corrugata
SOURCE: A. Magyarosy, D. Thomas
DISEASE: Pith necrosis
HOST: Geranium
Discolored stem caused by systemic infection of the pathogen.

Pith necrosis | Geranium
DISEASE: Pith necrosis
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Pseudomonas corrugata
SOURCE: A. Magyarosy, D. Thomas