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: Black chaff (Bacterial leaf streak)
HOST: Wheatgrass
Lesions on leaves first appear as water-soaked, translucent, long, narrow streaks. They later turn brown and necrotic and often coalesce into blighted areas.

Black chaff (Bacterial leaf streak) | Wheatgrass
DISEASE: Black chaff (Bacterial leaf streak)
HOST: Wheatgrass (Elytrigia intermedia)
PATHOGEN: Xanthomonas translucens pv. cerealis
SOURCE: S. Mohan
DISEASE: Black chaff (Bacterial leaf streak)
HOST: Wheatgrass
Close-up of leaf with brown necrotic streaks.

Black chaff (Bacterial leaf streak) | Wheatgrass
DISEASE: Black chaff (Bacterial leaf streak)
HOST: Wheatgrass (Elytrigia intermedia)
PATHOGEN: Xanthomonas translucens pv. cerealis
SOURCE: S. Mohan
DISEASE: X-disease (Eastern X)
HOST: Chokecherry
Shot-hole stage of X-disease.

X-disease (Eastern X) | Chokecherry
DISEASE: X-disease (Eastern X)
HOST: Chokecherry (Prunus virginiana)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: W. Sinclair
DISEASE: X-disease (Eastern X)
HOST: Chokecherry
X-disease causes rosettes and premature loss of leaves.

X-disease (Eastern X) | Chokecherry
DISEASE: X-disease (Eastern X)
HOST: Chokecherry (Prunus virginiana)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: W. Sinclair
DISEASE: X-disease (Eastern X)
HOST: Chokecherry
Chokecherry with stunted shoots, red leaves, and rosettes.

X-disease (Eastern X) | Chokecherry
DISEASE: X-disease (Eastern X)
HOST: Chokecherry (Prunus virginiana)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: W. Sinclair
DISEASE: X-disease (Eastern X)
HOST: Chokecherry
Chokecherry with red leaves, rosettes, and bud loss.

X-disease (Eastern X) | Chokecherry
DISEASE: X-disease (Eastern X)
HOST: Chokecherry (Prunus virginiana)
PATHOGEN: 'Candidatus Phytoplasma pruni'
PATHOGEN SYNONYM: Phytoplasma X-disease group
SOURCE: W. Sinclair