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: Goss's bacterial wilt and blight
HOST: Corn (Maize)
Wilted, dying plants. Leaves have gray to light yellow stripes and irregular margins that follow leaf veins. Systemically infected plants usually have orange vascular bundles.

Goss's bacterial wilt and blight | Corn (Maize)
DISEASE: Goss's bacterial wilt and blight
HOST: Corn (Maize) (Zea mays)
PATHOGEN: Clavibacter michiganensis subsp. nebraskensis
PATHOGEN SYNONYM: Corynebacterium nebraskense
SOURCE: A. Vidaver
DISEASE: Goss's bacterial wilt and blight
HOST: Corn (Maize)
The disease causes necrotic leaf lesions, which typically have dark flecks (freckles) within the lesions (not seen here).

Goss's bacterial wilt and blight | Corn (Maize)
DISEASE: Goss's bacterial wilt and blight
HOST: Corn (Maize) (Zea mays)
PATHOGEN: Clavibacter michiganensis subsp. nebraskensis
PATHOGEN SYNONYM: Corynebacterium nebraskense
SOURCE: A. Vidaver
DISEASE: Marginal leaf blight
HOST: Lettuce
Marginal leaf blight first appears as slimy wilting of leaf margins. Small, reddish lesions may be seen on leaf blades. Infected tissues turn brown to black in time.

Marginal leaf blight | Lettuce
DISEASE: Marginal leaf blight
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Pseudomonas marginalis
SOURCE: L. Fucikovsky