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: Larkspur virescence
HOST: Larkspur
Two diseased plants with stunted and small leaves, lack of flower coloration, and bunched flower buds. Healthy plant (left).
Larkspur virescence | Larkspur
DISEASE: Larkspur virescence
HOST: Larkspur (Delphinium sp.)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Raabe
DISEASE: Syringae seedling blight and leaf spot
HOST: Pepper
Blight lesions (on transplants) usually begin as water-soaked spots that later turn brown to black. Lesions are on cotyledons and first true leaves.
Syringae seedling blight and leaf spot | Pepper
DISEASE: Syringae seedling blight and leaf spot
HOST: Pepper (Capsicum annuum)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: APS