DISEASE: Bacterial blight
HOST: Grass
Timothy grass with light-colored lesions caused by unidentified Xanthomonas sp.

Bacterial blight | Grass
DISEASE: Bacterial blight
HOST: Grass (Phleum pratense)
PATHOGEN: Xanthomonas sp.
SOURCE: M. Shurtleff
DISEASE: Bacterial leaf spot (Blight)
HOST: Elderberry
Elderberry with dark brown to blackish angular leaf spots.

Bacterial leaf spot (Blight) | Elderberry
DISEASE: Bacterial leaf spot (Blight)
HOST: Elderberry (Sambucus racemosa)
PATHOGEN: Xanthomonas sp.
SOURCE: S. Mohan
DISEASE: Blister spot
HOST: Apple
Fruit with water-soaked spots.

Blister spot | Apple
DISEASE: Blister spot
HOST: Apple (Malus domestica)
PATHOGEN: Pseudomonas syringae pv. papulans
SOURCE: T. Burr
DISEASE: Blister spot
HOST: Apple
Water-soaked blister spots on leaves of blighted twig.

Blister spot | Apple
DISEASE: Blister spot
HOST: Apple (Malus domestica)
PATHOGEN: Pseudomonas syringae pv. papulans
SOURCE: T. Burr
DISEASE: Blister spot
HOST: Apple
Apple with brownish blister spots.

Blister spot | Apple
DISEASE: Blister spot
HOST: Apple (Malus domestica 'Mutsu')
PATHOGEN: Pseudomonas syringae pv. papulans
SOURCE: S. Thomson
DISEASE: Blister spot
HOST: Apple
Late stage of blister spot. The purplish black lesions are associated with lenticels and stomata.

Blister spot | Apple
DISEASE: Blister spot
HOST: Apple (Malus domestica 'Crispin')
PATHOGEN: Pseudomonas syringae pv. papulans
SOURCE: T. Burr
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