DISEASE: Bacterial leaf spot and canker
HOST: Sweetgum
Leaves with irregular necrotic lesions.

Bacterial leaf spot and canker | Sweetgum
DISEASE: Bacterial leaf spot and canker
HOST: Sweetgum (Liquidambar styraciflua)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: A. Bishop
DISEASE: Bacterial leaf spot and canker
HOST: Sweetgum
Stem canker of sweetgum.

Bacterial leaf spot and canker | Sweetgum
DISEASE: Bacterial leaf spot and canker
HOST: Sweetgum (Liquidambar styraciflua)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: A. Bishop
DISEASE: Pith necrosis
HOST: Geranium
Geranium with wilted, yellow necrotic leaves.

Pith necrosis | Geranium
DISEASE: Pith necrosis
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Pseudomonas corrugata
SOURCE: A. Magyarosy, D. Thomas
DISEASE: Pith necrosis
HOST: Geranium
Pitted and hollow stems, one of the disease symptoms.

Pith necrosis | Geranium
DISEASE: Pith necrosis
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Pseudomonas corrugata
SOURCE: A. Magyarosy, D. Thomas
DISEASE: Pith necrosis
HOST: Geranium
Discolored stem caused by systemic infection of the pathogen.

Pith necrosis | Geranium
DISEASE: Pith necrosis
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Pseudomonas corrugata
SOURCE: A. Magyarosy, D. Thomas
DISEASE: Pith necrosis
HOST: Tomato
Cracked, dry, hollow stems with internal necrosis.

Pith necrosis | Tomato
DISEASE: Pith necrosis
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas corrugata
SOURCE: A. Alvarez
DISEASE: Pith necrosis
HOST: Tomato
External necrotic stem tissues. Initial symptoms include chlorosis of young leaves. Wilting may occur when disease is severe.

Pith necrosis | Tomato
DISEASE: Pith necrosis
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas corrugata
SOURCE: K. Natsuaki, 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