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 (Bacterial necrosis)
HOST: Grape
Stem necrosis of grape.
Bacterial blight (Bacterial necrosis) | Grape
DISEASE: Bacterial blight (Bacterial necrosis)
HOST: Grape (Vitis vinifera)
PATHOGEN: Xylophilus ampelinus
PATHOGEN SYNONYM: Xanthomonas ampelina
SOURCE: N. Schaad
DISEASE: Bacterial blight (Bacterial necrosis)
HOST: Grape
Stem with cankers and discolored external tissues.
Bacterial blight (Bacterial necrosis) | Grape
DISEASE: Bacterial blight (Bacterial necrosis)
HOST: Grape (Vitis vinifera)
PATHOGEN: Xylophilus ampelinus
PATHOGEN SYNONYM: Xanthomonas ampelina
SOURCE: N. Schaad
DISEASE: Bacterial blight (Bacterial necrosis)
HOST: Grape
Severe infection in vineyard is noted by dead canes. Symptoms are most severe in spring; shoot blight, occasional spots on leaves, and cankers are common.
Bacterial blight (Bacterial necrosis) | Grape
DISEASE: Bacterial blight (Bacterial necrosis)
HOST: Grape (Vitis vinifera)
PATHOGEN: Xylophilus ampelinus
PATHOGEN SYNONYM: Xanthomonas ampelina
SOURCE: C. Manceau, N. Schaad
DISEASE: Bacterial blight (Bacterial necrosis)
HOST: Grape
Leaf with necrotic spots and marginal necrosis. One-sided cracking of petiole tissue is common (not shown here).
Bacterial blight (Bacterial necrosis) | Grape
DISEASE: Bacterial blight (Bacterial necrosis)
HOST: Grape (Vitis vinifera)
PATHOGEN: Xylophilus ampelinus
PATHOGEN SYNONYM: Xanthomonas ampelina
SOURCE: C. Panagopoulos
DISEASE: Bacterial blight
HOST: Geranium
Leaf with many necrotic spots and chlorotic V-shaped lesions.
Bacterial blight | Geranium
DISEASE: Bacterial blight
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Xanthomonas hortorum pv. pelargonii
PATHOGEN SYNONYM: Xanthomonas campestris pv. pelargonii
SOURCE: M. Daughtrey
DISEASE: Bacterial blight
HOST: Geranium
Blight symptoms are affected by environmental conditions and cultivar type. Here, large, sunken, brown, circular lesions have a brownish discoloration around some lesions.
Bacterial blight | Geranium
DISEASE: Bacterial blight
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Xanthomonas hortorum pv. pelargonii
PATHOGEN SYNONYM: Xanthomonas campestris pv. pelargonii
SOURCE: M. Daughtrey
DISEASE: Bacterial blight
HOST: Geranium
Geranium with wilted and necrotic leaves.
Bacterial blight | Geranium
DISEASE: Bacterial blight
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Xanthomonas hortorum pv. pelargonii
PATHOGEN SYNONYM: Xanthomonas campestris pv. pelargonii
SOURCE: R. Raabe
DISEASE: Bacterial blight
HOST: Geranium
Left and center leaves have spots, whereas leaf on right also has blight symptoms.
Bacterial blight | Geranium
DISEASE: Bacterial blight
HOST: Geranium (Pelargonium sp.)
PATHOGEN: Xanthomonas hortorum pv. pelargonii
PATHOGEN SYNONYM: Xanthomonas campestris pv. pelargonii
SOURCE: M. Shurtleff