DISEASE: Aster yellows
HOST: Watercress
Diseased watercress (left) and healthy plant (right).

Aster yellows | Watercress
DISEASE: Aster yellows
HOST: Watercress (Nasturtium officinale)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: W. Borth
DISEASE: Bacterial blight
HOST: Photinia
Symptoms of photinia bud blight shown here are similar to those of blast of pear and apple, caused by Pseudomonas syringae pv. syringae.

Bacterial blight | Photinia
DISEASE: Bacterial blight
HOST: Photinia (Photinia glabra)
PATHOGEN: Pseudomonas syringae pv. photiniae
SOURCE: M. Goto
DISEASE: Bacterial leaf spot
HOST: Ivy
Algerian ivy with mostly black spots without halos.

Bacterial leaf spot | Ivy
DISEASE: Bacterial leaf spot
HOST: Ivy (Hedera canariensis)
PATHOGEN: Xanthomonas hortorum pv. hederae
PATHOGEN SYNONYM: Xanthomonas campestris pv. hederae
SOURCE: M. Schroth
DISEASE: Bacterial leaf spot
HOST: Ivy
English ivy leaves with typical chlorotic halos around spots.

Bacterial leaf spot | Ivy
DISEASE: Bacterial leaf spot
HOST: Ivy (Hedera helix)
PATHOGEN: Xanthomonas hortorum pv. hederae
PATHOGEN SYNONYM: Xanthomonas campestris pv. hederae
SOURCE: S. Thomson
DISEASE: Fire blight
HOST: Photinia
Fire blight cankers on photinia.

Fire blight | Photinia
DISEASE: Fire blight
HOST: Photinia (Photinia fraseri)
PATHOGEN: Erwinia amylovora
SOURCE: M. Schroth