DISEASE: Aster yellows
HOST: Onion
Infected plants with yellowish, malformed leaves.

Aster yellows | Onion
DISEASE: Aster yellows
HOST: Onion (Allium cepa)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Rowe
DISEASE: Aster yellows
HOST: Onion
Onion flower with unusual symptoms (left) compared with healthy inflorescence (right). Flowers are distorted and often have abnormally long pedicels. Young leaves may have yellow streaks or a general yellowing of basal portions.

Aster yellows | Onion
DISEASE: Aster yellows
HOST: Onion (Allium cepa)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Raabe
DISEASE: Bacterial blast and black pit
HOST: Citrus (Lemon)
The term "black pit" refers to black lesions on fruit, which may be specks or large, sunken pits as seen here. They also may be light tan, later becoming reddish brown to black.

Bacterial blast and black pit | Citrus (Lemon)
DISEASE: Bacterial blast and black pit
HOST: Citrus (Lemon) (Citrus limon)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: J. Menge
DISEASE: Bacterial blight
HOST: Bean
Bean leaves with large necrotic areas.

Bacterial blight | Bean
DISEASE: Bacterial blight
HOST: Bean (Phaseolus vulgaris)
PATHOGEN: Xanthomonas axonopodis pv. phaseoli
PATHOGEN SYNONYM: Xanthomonas campestris pv. phaseoli
SOURCE: J. Young
DISEASE: Bacterial blight
HOST: Bean
Field of severely diseased beans.

Bacterial blight | Bean
DISEASE: Bacterial blight
HOST: Bean (Phaseolus vulgaris)
PATHOGEN: Xanthomonas axonopodis pv. phaseoli
PATHOGEN SYNONYM: Xanthomonas campestris pv. phaseoli
SOURCE: M. Shurtleff
DISEASE: Bacterial blight
HOST: Bean
Close-up of necrotic leaf lesions.

Bacterial blight | Bean
DISEASE: Bacterial blight
HOST: Bean (Phaseolus vulgaris)
PATHOGEN: Xanthomonas axonopodis pv. phaseoli
PATHOGEN SYNONYM: Xanthomonas campestris pv. phaseoli
SOURCE: A. Alvarez
DISEASE: Bacterial blight
HOST: Bean
Bean leaflet with large necrotic lesions surrounded by chlorotic zones.

Bacterial blight | Bean
DISEASE: Bacterial blight
HOST: Bean (Phaseolus vulgaris)
PATHOGEN: Xanthomonas axonopodis pv. phaseoli
PATHOGEN SYNONYM: Xanthomonas campestris pv. phaseoli
SOURCE: I. Hubbeling, J. van der Wolf
DISEASE: Bacterial blight
HOST: Bean
Seed infested with blight bacteria and insects. Bacterial blight is predominately seedborne.

Bacterial blight | Bean
DISEASE: Bacterial blight
HOST: Bean (Phaseolus vulgaris)
PATHOGEN: Xanthomonas axonopodis pv. phaseoli
PATHOGEN SYNONYM: Xanthomonas campestris pv. phaseoli
SOURCE: L. Claflin
DISEASE: Bacterial blight
HOST: Bean
Leaves of common bean with large necrotic spots bordered by yellow areas.

Bacterial blight | Bean
DISEASE: Bacterial blight
HOST: Bean (Phaseolus vulgaris)
PATHOGEN: Xanthomonas axonopodis pv. phaseoli
PATHOGEN SYNONYM: Xanthomonas campestris pv. phaseoli
SOURCE: E. Braun