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: Bacterial blast
HOST: Pear
The bacterium infects all flower parts and may spread and kill the entire spur.

Bacterial blast | Pear
DISEASE: Bacterial blast
HOST: Pear (Pyrus communis)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: W. Sinclair
DISEASE: Center rot
HOST: Onion
Early symptoms of disease are necrotic, bleached areas on young leaves that typically wilt.

Center rot | Onion
DISEASE: Center rot
HOST: Onion (Allium cepa)
PATHOGEN: Pantoea ananatis
SOURCE: R. Gitaitis
DISEASE: Center rot
HOST: Onion
Advanced stage of center rot. The bacterium has moved down from leaves into the bulb.

Center rot | Onion
DISEASE: Center rot
HOST: Onion (Allium cepa)
PATHOGEN: Pantoea ananatis
SOURCE: H. Schwartz