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: Chocolate spot
HOST: Corn (Maize)
Leaf with dark brown, elongated spots surrounded by broad, yellow halos.

Chocolate spot | Corn (Maize)
DISEASE: Chocolate spot
HOST: Corn (Maize) (Zea mays)
PATHOGEN: Pseudomonas syringae pv. coronafaciens
SOURCE: D. White
DISEASE: Syringae leaf spot
HOST: Tomato
Leaves with brown necrotic lesions and chlorotic margins. Symptoms vary greatly among cultivars. Some have black or brown lesions with bright yellow, chlorotic areas and others do not have yellowing.

Syringae leaf spot | Tomato
DISEASE: Syringae leaf spot
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: R. Gitaitis