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 hyperplastic canker
HOST: Almond
Diseased tree with multiple cankers. Margins of cankers are rough, soft, cheesy, dark brown, and have scalloped water-soaked spots that turn brown. Multiple cankers may girdle and kill small twigs.
Bacterial hyperplastic canker | Almond
DISEASE: Bacterial hyperplastic canker
HOST: Almond (Prunus dulcis)
PATHOGEN: Pseudomonas amygdali
SOURCE: P. Psallidas
DISEASE: Greasy center
HOST: Poinsettia
Stem with dark cankers and copious ooze. Necrotic areas are greasy in appearance and eventually turn light tan to brown with a papery texture as the cuticle becomes detached.
Greasy center | Poinsettia
DISEASE: Greasy center
HOST: Poinsettia (Euphorbia pulcherrima)
PATHOGEN: Pseudomonas viridiflava
SOURCE: R. Raabe