DISEASE: Bacterial leaf spot (Blight)
HOST: Poinsettia
Blighted leaves and stems.

Bacterial leaf spot (Blight) | Poinsettia
DISEASE: Bacterial leaf spot (Blight)
HOST: Poinsettia (Euphorbia pulcherrima)
PATHOGEN: Curtobacterium flaccumfaciens pv. poinsettiae
SOURCE: APS
DISEASE: Bacterial leaf spot (Blight)
HOST: Poinsettia
Poinsettia with diseased stem. Woody stems may have a yellowed cortex and dark vascular tissues. The stem tip may curve with deformed terminal leaves.

Bacterial leaf spot (Blight) | Poinsettia
DISEASE: Bacterial leaf spot (Blight)
HOST: Poinsettia (Euphorbia pulcherrima)
PATHOGEN: Curtobacterium flaccumfaciens pv. poinsettiae
SOURCE: APS
DISEASE: Bacterial leaf spot (Blight)
HOST: Poinsettia
Leaves with small, dark spots, an early stage of disease.

Bacterial leaf spot (Blight) | Poinsettia
DISEASE: Bacterial leaf spot (Blight)
HOST: Poinsettia (Euphorbia pulcherrima)
PATHOGEN: Curtobacterium flaccumfaciens pv. poinsettiae
SOURCE: A. Alvarez
DISEASE: Bacterial wilt and dieback
HOST: Willow
Cross sections of the characteristic "watermark stain" of diseased wood. Wilt and dieback occur as disease progresses.

Bacterial wilt and dieback | Willow
DISEASE: Bacterial wilt and dieback
HOST: Willow (Salix sp.)
PATHOGEN: Brenneria salicis
PATHOGEN SYNONYM: Erwinia salicis
SOURCE: Y. Sakamoto, M. Goto
DISEASE: Bacterial wilt and dieback
HOST: Willow
Severely diseased tree with dieback symptoms.

Bacterial wilt and dieback | Willow
DISEASE: Bacterial wilt and dieback
HOST: Willow (Salix sp.)
PATHOGEN: Brenneria salicis
PATHOGEN SYNONYM: Erwinia salicis
SOURCE: Y. Sakamoto, 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