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 wilt
HOST: Heliconia
Wilted and dying heliconia plant.
Bacterial wilt | Heliconia
DISEASE: Bacterial wilt
HOST: Heliconia (Heliconia sp.)
PATHOGEN: Ralstonia solanacearum
PATHOGEN SYNONYM: Pseudomonas solanacearum
SOURCE: I. Buddenhagen
DISEASE: Bacterial wilt
HOST: Heliconia
Heliconia spathes with wilt and leaf necrosis.
Bacterial wilt | Heliconia
DISEASE: Bacterial wilt
HOST: Heliconia (Heliconia sp.)
PATHOGEN: Ralstonia solanacearum
PATHOGEN SYNONYM: Pseudomonas solanacearum
SOURCE: I. Buddenhagen
DISEASE: Bacterial wilt
HOST: Heliconia
Heliconia stalk with discolored base.
Bacterial wilt | Heliconia
DISEASE: Bacterial wilt
HOST: Heliconia (Heliconia sp.)
PATHOGEN: Ralstonia solanacearum
PATHOGEN SYNONYM: Pseudomonas solanacearum
SOURCE: I. Buddenhagen
DISEASE: Bacterial wilt
HOST: Heliconia
Spathe of heliconia infected with bacterial wilt (right) compared with healthy spathe.
Bacterial wilt | Heliconia
DISEASE: Bacterial wilt
HOST: Heliconia (Heliconia sp.)
PATHOGEN: Ralstonia solanacearum
PATHOGEN SYNONYM: Pseudomonas solanacearum
SOURCE: I. Buddenhagen
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: Citrus canker
HOST: Citrus (Orange)
Leaf with leaf miner tunnels and numerous cankerlike lesions.
Citrus canker | Citrus (Orange)
DISEASE: Citrus canker
HOST: Citrus (Orange) (Citrus sinensis)
PATHOGEN: Xanthomonas citri subsp. citri
PATHOGEN SYNONYM: Xanthomonas citri
SOURCE: T. Gottwald
DISEASE: Citrus canker
HOST: Citrus (Orange)
Upper side of leaves with corky, raised lesions surrounded by yellow halos, a late stage of disease. Such infections usually are visible on lower sides of leaves first and soon after on upper sides.
Citrus canker | Citrus (Orange)
DISEASE: Citrus canker
HOST: Citrus (Orange) (Citrus sinensis)
PATHOGEN: Xanthomonas citri subsp. citri
PATHOGEN SYNONYM: Xanthomonas citri
SOURCE: J. H. Graham
DISEASE: Citrus canker
HOST: Citrus (Orange)
Yellowish halos are seen around lesions on the upper leaf surface, whereas lesions on the lower surface are more corky in appearance and have sunken centers without halos.
Citrus canker | Citrus (Orange)
DISEASE: Citrus canker
HOST: Citrus (Orange) (Citrus sinensis)
PATHOGEN: Xanthomonas citri subsp. citri
PATHOGEN SYNONYM: Xanthomonas citri
SOURCE: J. Young