DISEASE: Bacterial canker
HOST: Hazelnut
Primary symptoms are failure of buds to break and withering and death of new foliage in spring. Dead leaves remain attached to limbs after normal leaf fall.

Bacterial canker | Hazelnut
DISEASE: Bacterial canker
HOST: Hazelnut (Corylus americana)
PATHOGEN: Pseudomonas syringae pv. avellanae
PATHOGEN SYNONYM: Pseudomonas avellanae
SOURCE: P. Psalidas
DISEASE: Oleander knot
HOST: Oleander
Oleander with small knots/galls on leaf and stems.

Oleander knot | Oleander
DISEASE: Oleander knot
HOST: Oleander (Nerium oleander)
PATHOGEN: Pseudomonas savastanoi pv. nerii
SOURCE: W. Sinclair
DISEASE: Oleander knot
HOST: Oleander
Young stem with knots/galls.

Oleander knot | Oleander
DISEASE: Oleander knot
HOST: Oleander (Nerium oleander)
PATHOGEN: Pseudomonas savastanoi pv. nerii
SOURCE: R. Raabe
DISEASE: Oleander knot
HOST: Oleander
Leaf with early stage of knot/gall formation.

Oleander knot | Oleander
DISEASE: Oleander knot
HOST: Oleander (Nerium oleander)
PATHOGEN: Pseudomonas savastanoi pv. nerii
SOURCE: R. Raabe
DISEASE: Oleander knot
HOST: Oleander
Infected flowers with small knots/galls and necroses.

Oleander knot | Oleander
DISEASE: Oleander knot
HOST: Oleander (Nerium oleander)
PATHOGEN: Pseudomonas savastanoi pv. nerii
SOURCE: W. Sinclair
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