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: Aster yellows
HOST: Squash
Diagnostic characteristics for the disease are yellowing of young leaves, proliferation of secondary shoots, and rigid erect habit. Leaves are misshapen and smaller than normal and have stiff, thick laminae.
Aster yellows | Squash
DISEASE: Aster yellows
HOST: Squash (Cucurbita sp.)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: S. Miller
DISEASE: Bacterial canker and blast
HOST: Apricot
Apricot with typical reddish brown-discolored tissues beneath the bark and gumming around infected areas.
Bacterial canker and blast | Apricot
DISEASE: Bacterial canker and blast
HOST: Apricot (Prunus armeniaca)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: S. Sampson, M. Shurtleff
DISEASE: Bacterial canker and blast
HOST: Apricot
Young infected twig with droplets of bacterial ooze on stem.
Bacterial canker and blast | Apricot
DISEASE: Bacterial canker and blast
HOST: Apricot (Prunus armeniaca 'Moorpark')
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: J. Young
DISEASE: Bacterial canker and blast
HOST: Apricot
Bacterial canker has many symptoms. Typical symptoms are brown, sometimes reddish brown, internal tissues and rough, cracked bark.
Bacterial canker and blast | Apricot
DISEASE: Bacterial canker and blast
HOST: Apricot (Prunus armeniaca 'Moorpark')
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: J. Young
DISEASE: Bacterial canker and blast
HOST: Apricot
Infected apricot with sparse foliage (some twigs with no foliage) and a discolored area exposed where bark was removed.
Bacterial canker and blast | Apricot
DISEASE: Bacterial canker and blast
HOST: Apricot (Prunus armeniaca 'Moorpark')
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: J. Young
DISEASE: Bacterial canker and blast
HOST: Apricot
Fruit spot phase with numerous reddish necrotic spots.
Bacterial canker and blast | Apricot
DISEASE: Bacterial canker and blast
HOST: Apricot (Prunus armeniaca 'Moorpark')
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: J. Young
DISEASE: Bacterial leaf spot
HOST: Alfalfa
Stems with necrotic lesions.
Bacterial leaf spot | Alfalfa
DISEASE: Bacterial leaf spot
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Xanthomonas alfalfae subsp. alfalfae
PATHOGEN SYNONYM: Xanthomonas campestris pv. alfalfae
SOURCE: APS
DISEASE: Bacterial leaf spot
HOST: Alfalfa
Leaves with brown necrotic spots. Stems have water-soaked spots.
Bacterial leaf spot | Alfalfa
DISEASE: Bacterial leaf spot
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Xanthomonas alfalfae subsp. alfalfae
PATHOGEN SYNONYM: Xanthomonas campestris pv. alfalfae
SOURCE: S. Thomson