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
DISEASE: Brittle root
HOST: Horseradish
Horseradish with discolored internal tissues. Healthy root segment (top right).

Brittle root | Horseradish
DISEASE: Brittle root
HOST: Horseradish (Armoracia rusticana)
PATHOGEN: Spiroplasma citri
SOURCE: J. Fletcher, M. Davis
DISEASE: Bunch disease (Witches'-broom)
HOST: Butternut
Bunch disease of butternut.

Bunch disease (Witches'-broom) | Butternut
DISEASE: Bunch disease (Witches'-broom)
HOST: Butternut (Juglans cinerea)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: W. Sinclair
DISEASE: Fire blight
HOST: Apple
Severe infection of apple with dying twigs and branches.

Fire blight | Apple
DISEASE: Fire blight
HOST: Apple (Malus domestica)
PATHOGEN: Erwinia amylovora
SOURCE: S. Thomson
DISEASE: Fire blight
HOST: Apple
Diseased apple with copious ooze.

Fire blight | Apple
DISEASE: Fire blight
HOST: Apple (Malus domestica 'Jonathan')
PATHOGEN: Erwinia amylovora
SOURCE: S. Mohan
DISEASE: Fire blight
HOST: Apple
Canker on trunk oozing fire blight bacteria.

Fire blight | Apple
DISEASE: Fire blight
HOST: Apple (Malus domestica)
PATHOGEN: Erwinia amylovora
SOURCE: S. Thomson
DISEASE: Fire blight
HOST: Crabapple
Blighted shoot tip.

Fire blight | Crabapple
DISEASE: Fire blight
HOST: Crabapple (Malus sylvestris)
PATHOGEN: Erwinia amylovora
SOURCE: W. Sinclair