DISEASE: Aster yellows
HOST: Squash
Diagnostic characteristics for the disease are yellowing of young leaves, proliferation of secondary shoots, and rigid erect habit. Leaves are misshapen and smaller than normal and have stiff, thick laminae.
Aster yellows | Squash
DISEASE: Aster yellows
HOST: Squash (Cucurbita sp.)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: S. Miller
DISEASE: Bacterial leaf scorch
HOST: Pecan
Pecan with necrotic scorched leaves with distinct dark lines between healthy and diseased tissues.
Bacterial leaf scorch | Pecan
DISEASE: Bacterial leaf scorch
HOST: Pecan (Carya illinoinensis)
PATHOGEN: Xylella fastidiosa
SOURCE: T. Brenneman
DISEASE: Bacterial leaf spot and blight
HOST: Fern
Leaf with small lesions that coalesced into large, reddish brown necrotic area.
Bacterial leaf spot and blight | Fern
DISEASE: Bacterial leaf spot and blight
HOST: Fern (Asplenium nidus)
PATHOGEN: Burkholderia gladioli pv. gladioli
PATHOGEN SYNONYM: Pseudomonas gladioli pv. gladioli
SOURCE: APS
DISEASE: Bacterial leaf spot
HOST: Fern
Fronds with diseased tips.
Bacterial leaf spot | Fern
DISEASE: Bacterial leaf spot
HOST: Fern (Davallia fejeensis)
PATHOGEN: Burkholderia gladioli pv. gladioli
PATHOGEN SYNONYM: Pseudomonas gladioli pv. gladioli
SOURCE: APS
DISEASE: Bacterial leaf spot
HOST: Fern
Leaf with large, dark, longitudinal necrotic areas that differ from symptoms normally described for this disease.
Bacterial leaf spot | Fern
DISEASE: Bacterial leaf spot
HOST: Fern (Asplenium nidus)
PATHOGEN: Pseudomonas asplenii
SOURCE: R. Raabe
DISEASE: Bacterial leaf spot
HOST: Fern
Frond with brown necrotic spots.
Bacterial leaf spot | Fern
DISEASE: Bacterial leaf spot
HOST: Fern (Platycerium bifurcatum)
PATHOGEN: Burkholderia gladioli pv. gladioli
PATHOGEN SYNONYM: Pseudomonas gladioli pv. gladioli
SOURCE: APS
DISEASE: Bacterial wilt
HOST: Squash
Field with severe symptoms of wilt. Foliage often is chlorotic and leaf margins may be chlorotic and necrotic before plant death. Bacterial ooze may be seen streaming from the xylem when infected stems are cut.
Bacterial wilt | Squash
DISEASE: Bacterial wilt
HOST: Squash (Cucurbita maxima)
PATHOGEN: Erwinia tracheiphila
SOURCE: B. Jacobsen, M. Shurtleff
DISEASE: Bunch disease
HOST: Pecan
Pecan exhibiting bunch symptoms at ends of branches. This disease is thought to be caused by a phytoplasma similar to the walnut bunch pathogen in the X-disease group.
Bunch disease | Pecan
DISEASE: Bunch disease
HOST: Pecan (Carya illinoinensis)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: W. Sinclair
DISEASE: Bunch disease
HOST: Pecan
Severe case of bunch disease. Note bunches of foliage.
Bunch disease | Pecan
DISEASE: Bunch disease
HOST: Pecan (Carya illinoinensis)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: P. Bertrand