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 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: Bois noir disease
HOST: Grape
Severe symptoms of triangular-trapezoid-shaped leaves with desiccated appearance.
Bois noir disease | Grape
DISEASE: Bois noir disease
HOST: Grape (Vitis vinifera)
PATHOGEN: 'Candidatus Phytoplasma solani'
PATHOGEN SYNONYM: Phytoplasma Stolbur group
SOURCE: W. Schweigkofler
DISEASE: Bois noir disease
HOST: Grape
Leaves with disease symptoms identical to flavescence doree, a yellows disease caused by a different phytoplasma. The latter has a slightly different host range and is transmitted by a leafhopper.
Bois noir disease | Grape
DISEASE: Bois noir disease
HOST: Grape (Vitis vinifera)
PATHOGEN: 'Candidatus Phytoplasma solani'
PATHOGEN SYNONYM: Phytoplasma Stolbur group
SOURCE: W. Schweigkofler
DISEASE: Bois noir disease
HOST: Grape
Bois noir disease may be expressed on one branch while other branches appear healthy. Note trapezoid-shaped leaves.
Bois noir disease | Grape
DISEASE: Bois noir disease
HOST: Grape (Vitis vinifera 'Chardonnay')
PATHOGEN: 'Candidatus Phytoplasma solani'
PATHOGEN SYNONYM: Phytoplasma Stolbur group
SOURCE: W. Schweigkofler