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 spot
HOST: Elm
Leaf with small, dark brown lesions and necrosis along veins.
Bacterial leaf spot | Elm
DISEASE: Bacterial leaf spot
HOST: Elm (Ulmus americana)
PATHOGEN: Pseudomonas syringae pv. ulmi
SOURCE: W. Sinclair
DISEASE: Citrus canker
HOST: Citrus (sp. unknown)
Fruit with brown, corky lesions.
Citrus canker | Citrus (sp. unknown)
DISEASE: Citrus canker
HOST: Citrus (sp. unknown) (Citrus natsudaidai)
PATHOGEN: Xanthomonas citri subsp. citri
PATHOGEN SYNONYM: Xanthomonas citri
SOURCE: M. Goto
DISEASE: Citrus canker
HOST: Citrus (sp. unknown)
Leaf with corky lesions. Note absence of halos.
Citrus canker | Citrus (sp. unknown)
DISEASE: Citrus canker
HOST: Citrus (sp. unknown) (Citrus natsudaidai)
PATHOGEN: Xanthomonas citri subsp. citri
PATHOGEN SYNONYM: Xanthomonas citri
SOURCE: M. Goto
DISEASE: Citrus canker
HOST: Citrus (sp. unknown)
Twig with corky lesions.
Citrus canker | Citrus (sp. unknown)
DISEASE: Citrus canker
HOST: Citrus (sp. unknown) (Citrus natsudaidai)
PATHOGEN: Xanthomonas citri subsp. citri
PATHOGEN SYNONYM: Xanthomonas citri
SOURCE: M. Goto
DISEASE: Elm leaf scorch
HOST: Elm
Diseased tree with scorch at leaf margins.
Elm leaf scorch | Elm
DISEASE: Elm leaf scorch
HOST: Elm (Ulmus americana)
PATHOGEN: Xylella fastidiosa
SOURCE: J. Sherald, M. Shurtleff
DISEASE: Elm leaf scorch
HOST: Elm
Severely diseased tree with dieback and scorched leaves.
Elm leaf scorch | Elm
DISEASE: Elm leaf scorch
HOST: Elm (Ulmus americana)
PATHOGEN: Xylella fastidiosa
SOURCE: W. Sinclair
DISEASE: Elm yellows
HOST: Elm
Symptoms of elm yellows occasionally appear on one branch before others, but more often they involve the entire crown.
Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus americana)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair
DISEASE: Elm yellows
HOST: Elm
Diseased twig (right) with epinasty, chlorosis, and yellowing of leaves. Sometimes both yellow and green leaves occur on same branch. Healthy branch (left).
Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus americana)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair