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: Brown blotch
HOST: Mushroom
Stunted fruit bodies, initial stage of disease.

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Pleurotus ostreatus)
PATHOGEN: Pseudomonas tolaasii
SOURCE: K. Suyama, M. Goto
DISEASE: Brown blotch
HOST: Mushroom
Fruit bodies at advanced stage of disease.

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Pleurotus ostreatus)
PATHOGEN: Pseudomonas tolaasii
SOURCE: K. Suyama, M. Goto
DISEASE: Brown blotch
HOST: Mushroom
Black discoloration of basal portions of fruit bodies. Healthy (left).

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Flammulina velutipes)
PATHOGEN: Pseudomonas tolaasii
SOURCE: K. Suyama, M. Goto
DISEASE: Brown blotch
HOST: Mushroom
Black discoloration of basal portion of fruit bodies.

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Flammulina velutipes)
PATHOGEN: Pseudomonas tolaasii
SOURCE: K. Suyama, M. Goto
DISEASE: Brown blotch
HOST: Mushroom
Mushrooms with rotted, brownish discoloration of infected areas.

Brown blotch | Mushroom
DISEASE: Brown blotch
HOST: Mushroom (Agaricus campestris)
PATHOGEN: Pseudomonas tolaasii
SOURCE: J. Young
DISEASE: Pear decline
HOST: Pear
Healthy pear shoot (left) and diseased shoots (center and right). Leaves are reddish and growth is stunted.

Pear decline | Pear
DISEASE: Pear decline
HOST: Pear (Pyrus communis)
PATHOGEN: 'Candidatus Phytoplasma pyri'
PATHOGEN SYNONYM: Phytoplasma Apple proliferation group
SOURCE: S. Thomson
DISEASE: Pear decline
HOST: Pear
Close-up of infected pear branch showing premature reddish coloration of leaves and cupped, stunted leaves.

Pear decline | Pear
DISEASE: Pear decline
HOST: Pear (Pyrus communis)
PATHOGEN: 'Candidatus Phytoplasma pyri'
PATHOGEN SYNONYM: Phytoplasma Apple proliferation group
SOURCE: S. Thomson