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 leaf streak and bulb rot
HOST: Onion
The disease is characterized by dark spots on wrapper scales and/or reddish brown discoloration of inner scales.

Bacterial leaf streak and bulb rot | Onion
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion (Allium cepa)
PATHOGEN: Pseudomonas viridiflava
SOURCE: R. Gitaitis
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion
Onion with dead and rotted leaf at base of stem. Typical symptoms are water-soaked, dark green lesions that become oval with time, along with streaks and tipburn.

Bacterial leaf streak and bulb rot | Onion
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion (Allium cepa)
PATHOGEN: Pseudomonas viridiflava
SOURCE: H. Schwartz
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion
Browning and decay of bulb following inoculation with Pseudomonas viridiflava.

Bacterial leaf streak and bulb rot | Onion
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion (Allium cepa)
PATHOGEN: Pseudomonas viridiflava
SOURCE: R. Gitaitis
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion
Close-up of diseased leaves.

Bacterial leaf streak and bulb rot | Onion
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion (Allium cepa)
PATHOGEN: Pseudomonas viridiflava
SOURCE: R. Gitaitis
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion
Bulb rot with gray, bluish symptoms. Reddish brown discolorations also may occur.

Bacterial leaf streak and bulb rot | Onion
DISEASE: Bacterial leaf streak and bulb rot
HOST: Onion (Allium cepa)
PATHOGEN: Pseudomonas viridiflava
SOURCE: R. Gitaitis
DISEASE: Bacterial mosaic
HOST: Wheat
Diseased leaves with mosaic pattern exhibiting various amounts of yellowing. Leaves were artificially inoculated by vacuum infiltration.

Bacterial mosaic | Wheat
DISEASE: Bacterial mosaic
HOST: Wheat (Triticum aestivum)
PATHOGEN: Clavibacter michiganensis subsp. tessellarius
SOURCE: A. Vidaver