DISEASE: Blister spot
HOST: Apple
Late stage of blister spot. The purplish black lesions are associated with lenticels and stomata.

Blister spot | Apple
DISEASE: Blister spot
HOST: Apple (Malus domestica 'Crispin')
PATHOGEN: Pseudomonas syringae pv. papulans
SOURCE: T. Burr
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: Fire blight
HOST: Pluot
Fire blight cankers on major limb. Pluot is an interspecific hybrid of plum and apricot.

Fire blight | Pluot
DISEASE: Fire blight
HOST: Pluot (Prunus hybrid 'Dandy Dapple')
PATHOGEN: Erwinia amylovora
SOURCE: S. Mohan
DISEASE: Fire blight
HOST: Pluot
Dead shoot, the result of systemic infection.

Fire blight | Pluot
DISEASE: Fire blight
HOST: Pluot (Prunus hybrid 'Dandy Dapple')
PATHOGEN: Erwinia amylovora
SOURCE: S. Mohan