DISEASE: Bacterial blight (Brown stem)
HOST: Celery
Lesions are necrotic and circular to angular. Some have yellowish halos. Older lesions become brown and dry.

Bacterial blight (Brown stem) | Celery
DISEASE: Bacterial blight (Brown stem)
HOST: Celery (Apium graveolens)
PATHOGEN: Pseudomonas cichorii
SOURCE: R. Raid
DISEASE: Bacterial blight (Brown stem)
HOST: Celery
Ooze from lesion on celery leaf.

Bacterial blight (Brown stem) | Celery
DISEASE: Bacterial blight (Brown stem)
HOST: Celery (Apium graveolens)
PATHOGEN: Pseudomonas cichorii
SOURCE: R. Raid
DISEASE: Bacterial blight (Brown stem)
HOST: Celery
Characteristic brown discoloration of petioles, which is more evident on inside of petiole close to the crown. Parenchyma tissues are firm and brown.

Bacterial blight (Brown stem) | Celery
DISEASE: Bacterial blight (Brown stem)
HOST: Celery (Apium graveolens)
PATHOGEN: Pseudomonas cichorii
SOURCE: K. Pernezny
DISEASE: Bacterial shoot blight
HOST: Tea
Leaves with reddish brown spots.

Bacterial shoot blight | Tea
DISEASE: Bacterial shoot blight
HOST: Tea (Camellia sinensis)
PATHOGEN: Pseudomonas syringae pv. theae
SOURCE: M. Goto
DISEASE: Xanthomonas leaf blight
HOST: Onion
This was the first photo of onion leaf blight, which was considered a controversial finding for 10 years until an outbreak occurred in the West Indies.

Xanthomonas leaf blight | Onion
DISEASE: Xanthomonas leaf blight
HOST: Onion (Allium cepa)
PATHOGEN: Xanthomonas axonopodis pv. allii
PATHOGEN SYNONYM: Xanthomonas campestris pv. allii
SOURCE: A. Alvarez
DISEASE: Xanthomonas leaf blight
HOST: Onion
Diseased leaf with necrotic internal tissues.

Xanthomonas leaf blight | Onion
DISEASE: Xanthomonas leaf blight
HOST: Onion (Allium cepa)
PATHOGEN: Xanthomonas axonopodis pv. allii
PATHOGEN SYNONYM: Xanthomonas campestris pv. allii
SOURCE: A. Alvarez
DISEASE: Xanthomonas leaf blight
HOST: Onion
Onions with brown, necrotic, blighted leaves.

Xanthomonas leaf blight | Onion
DISEASE: Xanthomonas leaf blight
HOST: Onion (Allium cepa)
PATHOGEN: Xanthomonas axonopodis pv. allii
PATHOGEN SYNONYM: Xanthomonas campestris pv. allii
SOURCE: H. Schwartz
DISEASE: Xanthomonas leaf blight
HOST: Onion
Onions with severely blighted leaves.

Xanthomonas leaf blight | Onion
DISEASE: Xanthomonas leaf blight
HOST: Onion (Allium cepa)
PATHOGEN: Xanthomonas axonopodis pv. allii
PATHOGEN SYNONYM: Xanthomonas campestris pv. allii
SOURCE: H. Schwartz