DISEASE: Bacterial blight (Boll rot)
HOST: Cotton
Boll rot first appears as raised, water-soaked lesions, which become sunken and turn brown to black with time.

Bacterial blight (Boll rot) | Cotton
DISEASE: Bacterial blight (Boll rot)
HOST: Cotton (Gossypium barbadense)
PATHOGEN: Xanthomonas citri subsp. malvacearum
PATHOGEN SYNONYM: Xanthomonas campestris pv. malvacearum
SOURCE: A. Hayward
DISEASE: Bacterial blight (Boll rot)
HOST: Cotton
Infection of bolls causes premature opening and increased susceptibility to secondary, saprophytic microorganisms that cause rot. Note discolored cotton.

Bacterial blight (Boll rot) | Cotton
DISEASE: Bacterial blight (Boll rot)
HOST: Cotton (Gossypium barbadense)
PATHOGEN: Xanthomonas citri subsp. malvacearum
PATHOGEN SYNONYM: Xanthomonas campestris pv. malvacearum
SOURCE: APS
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: 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