DISEASE: Aster yellows
HOST: Ranunculus
Malformation of diseased flower.
![](/sites/default/files/plant_disease/images/0804.jpg)
Aster yellows | Ranunculus
DISEASE: Aster yellows
HOST: Ranunculus (Ranunculus sp.)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Raabe
DISEASE: Bacterial blight (Angular leaf spot)
HOST: Cotton
Leaf with advanced stage of blight.
![](/sites/default/files/plant_disease/images/0338.jpg)
Bacterial blight (Angular leaf spot) | Cotton
DISEASE: Bacterial blight (Angular leaf spot)
HOST: Cotton (Gossypium barbadense)
PATHOGEN: Xanthomonas citri subsp. malvacearum
PATHOGEN SYNONYM: Xanthomonas campestris pv. malvacearum
SOURCE: M. Shurtleff
DISEASE: Bacterial blight (Angular leaf spot)
HOST: Cotton
Highly susceptible (left) and resistant (right) cotton cultivars. The black arm stage of the disease is the most serious and occurs when bacteria invade petioles and then stems.
![](/sites/default/files/plant_disease/images/0339.jpg)
Bacterial blight (Angular leaf spot) | Cotton
DISEASE: Bacterial blight (Angular leaf spot)
HOST: Cotton (Gossypium barbadense)
PATHOGEN: Xanthomonas citri subsp. malvacearum
PATHOGEN SYNONYM: Xanthomonas campestris pv. malvacearum
SOURCE: APS
DISEASE: Bacterial blight (Angular leaf spot)
HOST: Cotton
Characteristic early symptoms are water-soaked leaf spots and water-soaking along veins.
![](/sites/default/files/plant_disease/images/0342.jpg)
Bacterial blight (Angular leaf spot) | Cotton
DISEASE: Bacterial blight (Angular leaf spot)
HOST: Cotton (Gossypium barbadense)
PATHOGEN: Xanthomonas citri subsp. malvacearum
PATHOGEN SYNONYM: Xanthomonas campestris pv. malvacearum
SOURCE: A. Hayward
DISEASE: Bacterial blight (Angular leaf spot)
HOST: Cotton
Leaf with dark, angular leaf spots. Systemic invasion causes blackening of midribs.
![](/sites/default/files/plant_disease/images/0337.jpg)
Bacterial blight (Angular leaf spot) | Cotton
DISEASE: Bacterial blight (Angular leaf spot)
HOST: Cotton (Gossypium barbadense)
PATHOGEN: Xanthomonas citri subsp. malvacearum
PATHOGEN SYNONYM: Xanthomonas campestris pv. malvacearum
SOURCE: APS
DISEASE: Bacterial blight (Boll rot)
HOST: Cotton
Boll rot first appears as raised, water-soaked lesions, which become sunken and turn brown to black with time.
![](/sites/default/files/plant_disease/images/0340.jpg)
Bacterial blight (Boll rot) | Cotton
DISEASE: Bacterial blight (Boll rot)
HOST: Cotton (Gossypium barbadense)
PATHOGEN: Xanthomonas citri subsp. malvacearum
PATHOGEN SYNONYM: Xanthomonas campestris pv. malvacearum
SOURCE: A. Hayward
DISEASE: Bacterial blight (Boll rot)
HOST: Cotton
Infection of bolls causes premature opening and increased susceptibility to secondary, saprophytic microorganisms that cause rot. Note discolored cotton.
![](/sites/default/files/plant_disease/images/0341.jpg)
Bacterial blight (Boll rot) | Cotton
DISEASE: Bacterial blight (Boll rot)
HOST: Cotton (Gossypium barbadense)
PATHOGEN: Xanthomonas citri subsp. malvacearum
PATHOGEN SYNONYM: Xanthomonas campestris pv. malvacearum
SOURCE: APS