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: Nephthytis
Leaf with concentric rings of dark tissues. There has been confusion of the causal agent with Dickeya sp., which also causes mushy leaf spots.
Bacterial leaf spot | Nephthytis
DISEASE: Bacterial leaf spot
HOST: Nephthytis (Syngonium podophyllum)
PATHOGEN: Pectobacterium carotovorum
PATHOGEN SYNONYM: Erwinia carotovora subsp. carotovora
SOURCE: A. Chase
DISEASE: Bacterial leaf spot
HOST: Nephthytis
Water-soaked tissues and large, dark brown necrotic areas at leaf margins. Healthy (center leaf).
Bacterial leaf spot | Nephthytis
DISEASE: Bacterial leaf spot
HOST: Nephthytis (Syngonium podophyllum)
PATHOGEN: Pseudomonas cichorii
SOURCE: S. Thomson
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: Drippy nut disease
HOST: Oak
Ooze from young twig inoculated with Brenneria quercina.
Drippy nut disease | Oak
DISEASE: Drippy nut disease
HOST: Oak (Quercus agrifolia)
PATHOGEN: Brenneria quercina
PATHOGEN SYNONYM: Erwinia quercina
SOURCE: M. Schroth
DISEASE: Drippy nut disease
HOST: Oak
Ooze from infected acorn. Copious ooze drips from infected acorns, leaving sticky spots on objects under tree canopy. Infections are associated with insect oviposit wounds.
Drippy nut disease | Oak
DISEASE: Drippy nut disease
HOST: Oak (Quercus agrifolia)
PATHOGEN: Brenneria quercina
PATHOGEN SYNONYM: Erwinia quercina
SOURCE: M. Schroth
DISEASE: Oak leaf scorch
HOST: Oak
Oak with scorched leaf tips.
Oak leaf scorch | Oak
DISEASE: Oak leaf scorch
HOST: Oak (Quercus kelloggii)
PATHOGEN: Xylella fastidiosa
SOURCE: S. Kostka
DISEASE: Oak leaf scorch
HOST: Oak
Leaf with brown, marginal necrosis resembling a burn.
Oak leaf scorch | Oak
DISEASE: Oak leaf scorch
HOST: Oak (Quercus rubra)
PATHOGEN: Xylella fastidiosa
SOURCE: W. Sinclair
DISEASE: Oak leaf scorch
HOST: Oak
Diseased tree with brownish, scorched leaves.
Oak leaf scorch | Oak
DISEASE: Oak leaf scorch
HOST: Oak (Quercus rubra)
PATHOGEN: Xylella fastidiosa
SOURCE: W. Sinclair