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: Brown blotch
HOST: Mushroom
Stunted fruit bodies, initial stage of disease.

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Pleurotus ostreatus)
PATHOGEN: Pseudomonas tolaasii
SOURCE: K. Suyama, M. Goto
DISEASE: Brown blotch
HOST: Mushroom
Fruit bodies at advanced stage of disease.

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Pleurotus ostreatus)
PATHOGEN: Pseudomonas tolaasii
SOURCE: K. Suyama, M. Goto
DISEASE: Brown blotch
HOST: Mushroom
Black discoloration of basal portions of fruit bodies. Healthy (left).

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Flammulina velutipes)
PATHOGEN: Pseudomonas tolaasii
SOURCE: K. Suyama, M. Goto
DISEASE: Brown blotch
HOST: Mushroom
Black discoloration of basal portion of fruit bodies.

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Flammulina velutipes)
PATHOGEN: Pseudomonas tolaasii
SOURCE: K. Suyama, M. Goto
DISEASE: Brown blotch
HOST: Mushroom
Mushrooms with rotted, brownish discoloration of infected areas.

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Agaricus campestris)
PATHOGEN: Pseudomonas tolaasii
SOURCE: J. Young
DISEASE: Corky root
HOST: Lettuce
Corky root causes a reduction in size of lettuce heads and root systems; susceptible cultivar (right) and resistant cultivar (left).

Corky root | Lettuce
DISEASE: Corky root
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Sphingomonas suberifaciens
PATHOGEN SYNONYM: Rhizomonas suberifaciens
SOURCE: E. J. Ryder