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: 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: Fire blight
HOST: Plum
Typical symptoms of fire blight-infected, young European plum shoot.

Fire blight | Plum
DISEASE: Fire blight
HOST: Plum (Prunus domestica 'Empress')
PATHOGEN: Erwinia amylovora
SOURCE: S. Mohan