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 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 canker
HOST: Hazelnut
Primary symptoms are failure of buds to break and withering and death of new foliage in spring. Dead leaves remain attached to limbs after normal leaf fall.

Bacterial canker | Hazelnut
DISEASE: Bacterial canker
HOST: Hazelnut (Corylus americana)
PATHOGEN: Pseudomonas syringae pv. avellanae
PATHOGEN SYNONYM: Pseudomonas avellanae
SOURCE: P. Psalidas
DISEASE: Bacterial finger-tip rot
HOST: Banana
Cross sections of fruit with internal discoloration and rot. This disease is also known as Mokillo disease.

Bacterial finger-tip rot | Banana
DISEASE: Bacterial finger-tip rot
HOST: Banana (Musa sp.)
PATHOGEN: Burkholderia cenocepacia
PATHOGEN SYNONYM: Pseudomonas cenocepacia
SOURCE: I. Buddenhagen
DISEASE: Bacterial finger-tip rot
HOST: Banana
Longitudinal sections of fruit with internal discoloration and rot. Healthy (right).

Bacterial finger-tip rot | Banana
DISEASE: Bacterial finger-tip rot
HOST: Banana (Musa sp.)
PATHOGEN: Burkholderia cenocepacia
PATHOGEN SYNONYM: Pseudomonas cenocepacia
SOURCE: I. Buddenhagen
DISEASE: Bacterial finger-tip rot
HOST: Banana
Diseased banana hand with external discoloration.

Bacterial finger-tip rot | Banana
DISEASE: Bacterial finger-tip rot
HOST: Banana (Musa sp.)
PATHOGEN: Burkholderia cenocepacia
PATHOGEN SYNONYM: Pseudomonas cenocepacia
SOURCE: I. Buddenhagen
DISEASE: Bacterial leaf spot
HOST: Alfalfa
Stems with necrotic lesions.

Bacterial leaf spot | Alfalfa
DISEASE: Bacterial leaf spot
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Xanthomonas alfalfae subsp. alfalfae
PATHOGEN SYNONYM: Xanthomonas campestris pv. alfalfae
SOURCE: APS
DISEASE: Bacterial leaf spot
HOST: Alfalfa
Leaves with brown necrotic spots. Stems have water-soaked spots.

Bacterial leaf spot | Alfalfa
DISEASE: Bacterial leaf spot
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Xanthomonas alfalfae subsp. alfalfae
PATHOGEN SYNONYM: Xanthomonas campestris pv. alfalfae
SOURCE: S. Thomson