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 soft rot
HOST: Orchid
Oncidium orchid with translucence and rot of central leaves.

Bacterial soft rot | Orchid
DISEASE: Bacterial soft rot
HOST: Orchid (Oncidium sp.)
PATHOGEN: Pectobacterium carotovorum
PATHOGEN SYNONYM: Erwinia carotovora subsp. carotovora
SOURCE: R. McMillan
DISEASE: Bacterial stem rot
HOST: Orchid
Oncidium orchid with rot at base of stem.

Bacterial stem rot | Orchid
DISEASE: Bacterial stem rot
HOST: Orchid (Oncidium sp.)
PATHOGEN: Burkholderia andropogonis
PATHOGEN SYNONYM: Pseudomonas andropogonis
SOURCE: A. Alvarez
DISEASE: Brittle root
HOST: Horseradish
Dying, stunted, yellow to brown horseradish plants.

Brittle root | Horseradish
DISEASE: Brittle root
HOST: Horseradish (Armoracia rusticana)
PATHOGEN: Spiroplasma citri
SOURCE: C. Eastman, M. Davis
DISEASE: Brittle root
HOST: Horseradish
Close-up of stunted, yellow horseradish plants.

Brittle root | Horseradish
DISEASE: Brittle root
HOST: Horseradish (Armoracia rusticana)
PATHOGEN: Spiroplasma citri
SOURCE: D. Sherrod