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: Grass
Wilted and dead patches of diseased creeping bent grass (Toronto grass) on golf green.
Bacterial wilt | Grass
DISEASE: Bacterial wilt
HOST: Grass (Agrostis stolonifera)
PATHOGEN: Xanthomonas translucens pv. poae
SOURCE: D. Roberts
DISEASE: Bacterial wilt
HOST: Grass
Irregular disease patterns on golf green. The cultivars Toronto, Cohansey, and Nimisilia are primary hosts of the disease.
Bacterial wilt | Grass
DISEASE: Bacterial wilt
HOST: Grass (Agrostis stolonifera)
PATHOGEN: Xanthomonas translucens pv. poae
SOURCE: D. Roberts
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: 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
Removal of bark revealed pitted vascular tissues.
Deep bark canker | Walnut
DISEASE: Deep bark canker
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Brenneria rubrifaciens
PATHOGEN SYNONYM: Erwinia rubrifaciens
SOURCE: N. Schaad
DISEASE: Deep bark canker
HOST: Walnut
Dead limbs are characteristic of advanced stage of disease.
Deep bark canker | Walnut
DISEASE: Deep bark canker
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Brenneria rubrifaciens
PATHOGEN SYNONYM: Erwinia rubrifaciens
SOURCE: N. Schaad
DISEASE: Shallow bark canker
HOST: Walnut
Diseased, discolored tissues revealed by removing external bark.
Shallow bark canker | Walnut
DISEASE: Shallow bark canker
HOST: Walnut (Juglans regia 'Hartley')
PATHOGEN: Brenneria nigrifluens
PATHOGEN SYNONYM: Erwinia nigrifluens
SOURCE: B. Teviotdale