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 blight
HOST: Spathiphyllum
Progression of disease severity on leaves from right to left.
Bacterial blight | Spathiphyllum
DISEASE: Bacterial blight
HOST: Spathiphyllum (Spathiphyllum sp.)
PATHOGEN: Xanthomonas axonopodis pv. dieffenbachiae
PATHOGEN SYNONYM: Xanthomonas campestris pv. dieffenbachiae
SOURCE: A. Alvarez
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: Bunch disease
HOST: Walnut
Foliage with bunchlike symptoms.
Bunch disease | Walnut
DISEASE: Bunch disease
HOST: Walnut (Juglans nigra)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: R. Green
DISEASE: Bunch disease
HOST: Walnut
Twisted shoot with yellow leaves, a symptom of bunch disease.
Bunch disease | Walnut
DISEASE: Bunch disease
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: E. Braun
DISEASE: Bunch disease
HOST: Walnut
Tree with advanced disease symptoms of branch and twig death.
Bunch disease | Walnut
DISEASE: Bunch disease
HOST: Walnut (Juglans microcarpa)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: W. Sinclair
DISEASE: Deep bark canker
HOST: Walnut
Reddish brown exudate flowing from longitudinal cracks in the trunk. Cankers are deep extending into wood.
Deep bark canker | Walnut
DISEASE: Deep bark canker
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Brenneria rubrifaciens
PATHOGEN SYNONYM: Erwinia rubrifaciens
SOURCE: B. Teviotdale
DISEASE: Deep bark canker
HOST: Walnut
Reddish brown exudate flowing from cracks in trunk, a result of systemic invasion by the bacterium.
Deep bark canker | Walnut
DISEASE: Deep bark canker
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Brenneria rubrifaciens
PATHOGEN SYNONYM: Erwinia rubrifaciens
SOURCE: B. Teviotdale
DISEASE: Deep bark canker
HOST: Walnut
Pits in the wood and black streaks in inner bark are key diagnostic symptoms.
Deep bark canker | Walnut
DISEASE: Deep bark canker
HOST: Walnut (Juglans regia)
PATHOGEN: Brenneria rubrifaciens
PATHOGEN SYNONYM: Erwinia rubrifaciens
SOURCE: N. Schaad, M. Schroth