DISEASE: Aster yellows
HOST: Kalanchoe
Kalanchoe with malformed inflorescences.

Aster yellows | Kalanchoe
DISEASE: Aster yellows
HOST: Kalanchoe (Kalanchoe sp.)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Raabe
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: Crown gall
HOST: Grape
Gall on base of 'Zinfandel' grape in California, where aerial galls are less common because of dry, hot weather.

Crown gall | Grape
DISEASE: Crown gall
HOST: Grape (Vitis vinifera 'Zinfandel')
PATHOGEN: Agrobacterium vitis
PATHOGEN SYNONYM: Rhizobium vitus
SOURCE: M. Schroth