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: Wheat
Healthy head (left) and diseased head (right). Diseased seedlings may die within 2 to 3 weeks. Infected heads of surviving plants are small and sterile, with distorted awns.
Aster yellows | Wheat
DISEASE: Aster yellows
HOST: Wheat (Triticum aestivum)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: L. N. Chiykowski
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine
Dark cankers on last year's twig. Symptoms of bacterial dieback of nectarine are identical to those of bacterial dieback of peach.
Bacterial dieback of nectarine | Nectarine
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine (Prunus persica var. nucipersica)
PATHOGEN: Pseudomonas syringae pv. persicae
SOURCE: J. Young
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine
Diseased young twigs.
Bacterial dieback of nectarine | Nectarine
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine (Prunus persica var. nucipersica)
PATHOGEN: Pseudomonas syringae pv. persicae
SOURCE: J. Young
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine
Bacterial invasion of trunk caused reddish brown discolored area. Symptoms of bacterial dieback of nectarine are identical to those of bacterial dieback of peach.
Bacterial dieback of nectarine | Nectarine
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine (Prunus persica var. nucipersica)
PATHOGEN: Pseudomonas syringae pv. persicae
SOURCE: J. Young
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine
Discolored vascular tissues and gummosis on infected twig.
Bacterial dieback of nectarine | Nectarine
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine (Prunus persica var. nucipersica)
PATHOGEN: Pseudomonas syringae pv. persicae
SOURCE: J. Young
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine
Symptoms of the disease include leaf spots (top leaf). Similar appearing leaf spots may be caused by Xanthomonas arboricola pv. pruni (bottom leaf).
Bacterial dieback of nectarine | Nectarine
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine (Prunus persica var. nucipersica)
PATHOGEN: Pseudomonas syringae pv. persicae
SOURCE: J. Young
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine
Dying tree caused by systemic invasion of the bacterium. Symptoms of bacterial dieback of nectarine are identical to those of bacterial dieback of peach.
Bacterial dieback of nectarine | Nectarine
DISEASE: Bacterial dieback of nectarine
HOST: Nectarine (Prunus persica var. nucipersica)
PATHOGEN: Pseudomonas syringae pv. persicae
SOURCE: J. Young
DISEASE: Bacterial leaf blight
HOST: Wheat
Diseased leaves with whitish blotches. Initial water-soaked spots become necrotic and progress from gray-green to tannish white.
Bacterial leaf blight | Wheat
DISEASE: Bacterial leaf blight
HOST: Wheat (Triticum aestivum)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: J. Otta