DISEASE: Alfalfa dwarf
HOST: Alfalfa
Alfalfa dwarf is characterized by stunted plants (left), usually dark blue-green in color. Xylem tissues become brown, especially when exposed to air.
Alfalfa dwarf | Alfalfa
DISEASE: Alfalfa dwarf
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Xylella fastidiosa
SOURCE: R. M. Davis
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: Walnut blight
HOST: Walnut
Typical symptoms of infected leaf and young nutlets. Infected young, growing leaves usually become malformed.
Walnut blight | Walnut
DISEASE: Walnut blight
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Xanthomonas arboricola pv. juglandis
SOURCE: M. Schroth
DISEASE: Walnut blight
HOST: Walnut
Tree with severely blighted foliage.
Walnut blight | Walnut
DISEASE: Walnut blight
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Xanthomonas arboricola pv. juglandis
SOURCE: M. Schroth
DISEASE: Walnut blight
HOST: Walnut
Nuts with side blight. Infections also are commonly found at stylar ends.
Walnut blight | Walnut
DISEASE: Walnut blight
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Xanthomonas arboricola pv. juglandis
SOURCE: B. Teviotdale
DISEASE: Walnut blight
HOST: Walnut
Nuts with decayed kernels.
Walnut blight | Walnut
DISEASE: Walnut blight
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Xanthomonas arboricola pv. juglandis
SOURCE: B. Teviotdale
DISEASE: Walnut blight
HOST: Walnut
Three catkins with different degrees of infection.
Walnut blight | Walnut
DISEASE: Walnut blight
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Xanthomonas arboricola pv. juglandis
SOURCE: M. Schroth