DISEASE: Aster yellows
HOST: Barley
Infection by this phytoplasm causes twisted awns and sterile florets.

Aster yellows | Barley
DISEASE: Aster yellows
HOST: Barley (Hordeum vulgare)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: E. Banttari
DISEASE: Aster yellows
HOST: Barley
Small necrotic spots on lower leaves and red coalescing streaks on upper leaves.

Aster yellows | Barley
DISEASE: Aster yellows
HOST: Barley (Hordeum vulgare)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: E. Banttari
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 kernel blight (Leaf blight)
HOST: Barley
Dark, brown discolored kernels at the embryo end and posterior surface.

Bacterial kernel blight (Leaf blight) | Barley
DISEASE: Bacterial kernel blight (Leaf blight)
HOST: Barley (Hordeum vulgare)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: C. Martinez-Miller
DISEASE: Bacterial leaf blight
HOST: Barley
Diseased barley plants with typical bleaching of flag leaves. Initial symptoms are water-soaked lesions that later coalesce. Eventually, the entire leaf becomes necrotic and edges roll inward.

Bacterial leaf blight | Barley
DISEASE: Bacterial leaf blight
HOST: Barley (Hordeum vulgare)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: D. Sands
DISEASE: Bacterial soft rot
HOST: Orchid
Oncidium orchid with translucence and rot of central leaves.

Bacterial soft rot | Orchid
DISEASE: Bacterial soft rot
HOST: Orchid (Oncidium sp.)
PATHOGEN: Pectobacterium carotovorum
PATHOGEN SYNONYM: Erwinia carotovora subsp. carotovora
SOURCE: R. McMillan
DISEASE: Bacterial stem rot
HOST: Orchid
Oncidium orchid with rot at base of stem.

Bacterial stem rot | Orchid
DISEASE: Bacterial stem rot
HOST: Orchid (Oncidium sp.)
PATHOGEN: Burkholderia andropogonis
PATHOGEN SYNONYM: Pseudomonas andropogonis
SOURCE: A. Alvarez
DISEASE: Black chaff (Bacterial leaf streak)
HOST: Barley
Black chaff is characterized by water-soaked and darkened glumes on barley heads and streaks and stripes on leaves.

Black chaff (Bacterial leaf streak) | Barley
DISEASE: Black chaff (Bacterial leaf streak)
HOST: Barley (Hordeum vulgare)
PATHOGEN: Xanthomonas translucens pv. undulosa
SOURCE: S. Thomson
DISEASE: Black chaff (Bacterial leaf streak)
HOST: Barley
Leaf with linear, water-soaked lesions that turn necrotic and brown. Flakes of dry bacterial exudate are apparent on the lesions. The pathogen also causes black glume of barley.

Black chaff (Bacterial leaf streak) | Barley
DISEASE: Black chaff (Bacterial leaf streak)
HOST: Barley (Hordeum vulgare)
PATHOGEN: Xanthomonas translucens pv. undulosa
SOURCE: S. Thomson