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: Sumatra disease
HOST: Clove
Diseased tree with defoliation and dieback.

Sumatra disease | Clove
DISEASE: Sumatra disease
HOST: Clove (Syzygium aromaticum)
PATHOGEN: Ralstonia syzygii
SOURCE: A. Hayward
DISEASE: Xanthomonas leaf spot
HOST: Cabbage
Cabbage leaf with small lesions. Lesions may enlarge and coalesce, causing distortion. Stem lesions are black and sunken and may cause death of the plants.

Xanthomonas leaf spot | Cabbage
DISEASE: Xanthomonas leaf spot
HOST: Cabbage (Brassica oleracea var. capitata)
PATHOGEN: Xanthomonas campestris pv. raphani
SOURCE: R. Gitaitis