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 (Head rot)
HOST: Lettuce
Leaf with black, greasy spots that tend to be vein delimited. Lesions begin as small, angular, water-soaked lesions that coalesce, resulting in large necrotic areas.
Bacterial leaf spot (Head rot) | Lettuce
DISEASE: Bacterial leaf spot (Head rot)
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Xanthomonas axonopodis pv. vitians
PATHOGEN SYNONYM: Xanthomonas campestris pv. vitians
SOURCE: A. Alvarez
DISEASE: Bacterial stalk and top rot
HOST: Corn (Maize)
Corn exhibiting symptoms at early stage of disease. Note water-soaked external stalk tissues.
Bacterial stalk and top rot | Corn (Maize)
DISEASE: Bacterial stalk and top rot
HOST: Corn (Maize) (Zea mays 'Pukekohe')
PATHOGEN: Dickeya zeae
PATHOGEN SYNONYM: Erwinia chrysanthemi pv. zeae
SOURCE: J. Young
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
DISEASE: Corky root
HOST: Lettuce
Corky root causes a reduction in size of lettuce heads and root systems; susceptible cultivar (right) and resistant cultivar (left).
Corky root | Lettuce
DISEASE: Corky root
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Sphingomonas suberifaciens
PATHOGEN SYNONYM: Rhizomonas suberifaciens
SOURCE: E. J. Ryder
DISEASE: Corky root
HOST: Lettuce
Close-up of root with malformed, corky appearance and longitudinal ridges of brown tissues.
Corky root | Lettuce
DISEASE: Corky root
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Sphingomonas suberifaciens
PATHOGEN SYNONYM: Rhizomonas suberifaciens
SOURCE: A. van Bruggen
DISEASE: Corky root
HOST: Lettuce
Initial symptoms of disease are yellow lesions on taproot and main laterals. Greenish brown bands occur around roots. Root pith may become brown and hollow.
Corky root | Lettuce
DISEASE: Corky root
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Sphingomonas suberifaciens
PATHOGEN SYNONYM: Rhizomonas suberifaciens
SOURCE: A. van Bruggen
DISEASE: Corky root
HOST: Lettuce
Differences in corky root symptoms between susceptible cultivar (right) and resistant cultivar (left).
Corky root | Lettuce
DISEASE: Corky root
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Sphingomonas suberifaciens
PATHOGEN SYNONYM: Rhizomonas suberifaciens
SOURCE: E. Ryder