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 leaf spot
HOST: Snapdragon
Leaves with large necrotic areas with brownish centers and purplish margins. Lesions are slightly sunken.
Bacterial leaf spot | Snapdragon
DISEASE: Bacterial leaf spot
HOST: Snapdragon (Antirrhinum majus)
PATHOGEN: Pseudomonas syringae pv. antirrhini
SOURCE: R. Raabe
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: Phytoplasma disease
HOST: Daffodil
Phytoplasma disease of daffodil. Healthy (right).
Phytoplasma disease | Daffodil
DISEASE: Phytoplasma disease
HOST: Daffodil (Narcissus pseudonarcissus)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: R. Raabe