DISEASE: Bacterial blast
HOST: Pear
The bacterium infects all flower parts and may spread and kill the entire spur.
![](/sites/default/files/plant_disease/images/0696.jpg)
Bacterial blast | Pear
DISEASE: Bacterial blast
HOST: Pear (Pyrus communis)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: W. Sinclair
DISEASE: Bacterial leaf spot
HOST: Collard
Leaf with several kinds of spots. Small necrotic lesions with yellow halos, brown lesions, and large, brown necrotic areas caused by coalescing of lesions.
![](/sites/default/files/plant_disease/images/0310.jpg)
Bacterial leaf spot | Collard
DISEASE: Bacterial leaf spot
HOST: Collard (Brassica oleracea var. acephala)
PATHOGEN: Pseudomonas syringae pv. maculicola
SOURCE: S. Miller
DISEASE: Crown gall
HOST: Pear
Crown gall of pear rootstock.
![](/sites/default/files/plant_disease/images/0680.jpg)
Crown gall | Pear
DISEASE: Crown gall
HOST: Pear (Pyrus communis)
PATHOGEN: Agrobacterium tumefaciens
PATHOGEN SYNONYM: Rhizobium sp.
SOURCE: H. Sawada, M. Goto
DISEASE: Fire blight
HOST: Pear
Blighted shoot and blossoms.
![](/sites/default/files/plant_disease/images/0686.jpg)
Fire blight | Pear
DISEASE: Fire blight
HOST: Pear (Pyrus communis)
PATHOGEN: Erwinia amylovora
SOURCE: M. Schroth
DISEASE: Fire blight
HOST: Pear
Typical appearance of advanced stage of disease after the bacterium invades from shoot tips/flowers downward.
![](/sites/default/files/plant_disease/images/0688.jpg)
Fire blight | Pear
DISEASE: Fire blight
HOST: Pear (Pyrus communis)
PATHOGEN: Erwinia amylovora
SOURCE: M. Schroth
DISEASE: Fire blight
HOST: Pear
The disease causes lack of leaf detachment on infected branches, commonly seen during California winters.
![](/sites/default/files/plant_disease/images/0689.jpg)
Fire blight | Pear
DISEASE: Fire blight
HOST: Pear (Pyrus communis)
PATHOGEN: Erwinia amylovora
SOURCE: M. Schroth
DISEASE: Fire blight
HOST: Pear
Diseased fruit.
![](/sites/default/files/plant_disease/images/0690.jpg)
Fire blight | Pear
DISEASE: Fire blight
HOST: Pear (Pyrus communis)
PATHOGEN: Erwinia amylovora
SOURCE: M. Schroth
DISEASE: Fire blight
HOST: Pear
Bacterial strands may form on blossoms and young fruit under humid conditions.
![](/sites/default/files/plant_disease/images/0691.jpg)
Fire blight | Pear
DISEASE: Fire blight
HOST: Pear (Pyrus communis)
PATHOGEN: Erwinia amylovora
SOURCE: S. Thomson