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: Crown gall
HOST: Forsythia
Crown galls on forsythia stems.

Crown gall | Forsythia
DISEASE: Crown gall
HOST: Forsythia (Forsythia sp.)
PATHOGEN: Agrobacterium tumefaciens
PATHOGEN SYNONYM: Rhizobium sp.
SOURCE: M. Shurtleff
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