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
DISEASE: Sweet potato little leaf
HOST: Sweet potato
Infected plant (left) and healthy plant (right).

Sweet potato little leaf | Sweet potato
DISEASE: Sweet potato little leaf
HOST: Sweet potato (Ipomoea batatas)
PATHOGEN: 'Candidatus Phytoplasma aurantifolia'
PATHOGEN SYNONYM: Phytoplasma Peanut witches'-broom group
SOURCE: R. McCoy, M. Davis
DISEASE: Sweet potato scab
HOST: Sweet potato
Tubers with large, dark scabs.

Sweet potato scab | Sweet potato
DISEASE: Sweet potato scab
HOST: Sweet potato (Ipomoea batatas)
PATHOGEN: Streptomyces ipomoeae
SOURCE: APS
DISEASE: Sweet potato scab
HOST: Sweet potato
Black and necrotic decay of fibrous roots.

Sweet potato scab | Sweet potato
DISEASE: Sweet potato scab
HOST: Sweet potato (Ipomoea batatas)
PATHOGEN: Streptomyces ipomoeae
SOURCE: W. Martin
DISEASE: Witches'-broom
HOST: Citrus (Lime)
Lime tree with compact, small leaves (witches'-broom). Leaves on older brooms dry out and eventually drop, leaving dead, bare branches. There are no flowers or fruit on brooms.

Witches'-broom | Citrus (Lime)
DISEASE: Witches'-broom
HOST: Citrus (Lime) (Citrus sp.)
PATHOGEN: 'Candidatus Phytoplasma aurantifolia'
PATHOGEN SYNONYM: Phytoplasma Peanut witches'-broom group
SOURCE: J. Bove, M. Garnier