DISEASE: Aster yellows
HOST: Watercress
Diseased watercress (left) and healthy plant (right).
Aster yellows | Watercress
DISEASE: Aster yellows
HOST: Watercress (Nasturtium officinale)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: W. Borth
DISEASE: Aster yellows
HOST: Wheat
Healthy head (left) and diseased head (right). Diseased seedlings may die within 2 to 3 weeks. Infected heads of surviving plants are small and sterile, with distorted awns.
Aster yellows | Wheat
DISEASE: Aster yellows
HOST: Wheat (Triticum aestivum)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: L. N. Chiykowski
DISEASE: Aster yellows
HOST: Zinnia
Yellowing and shoot proliferation of foliage.
Aster yellows | Zinnia
DISEASE: Aster yellows
HOST: Zinnia (Zinnia violacea)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: J. Forsberg, M. Shurtleff
DISEASE: Bacterial speck
HOST: Tomato
Leaf with typical brown to black lesions without halos, an early stage of disease.
Bacterial speck | Tomato
DISEASE: Bacterial speck
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas syringae pv. tomato
SOURCE: S. Thomson
DISEASE: Bacterial speck
HOST: Tomato
Leaves with spots, some surrounded by chlorotic zones.
Bacterial speck | Tomato
DISEASE: Bacterial speck
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas syringae pv. tomato
SOURCE: R. Gitaitis
DISEASE: Bacterial speck
HOST: Tomato
Curling leaves with large, blackish lesions. Later, yellowing occurs around lesions.
Bacterial speck | Tomato
DISEASE: Bacterial speck
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas syringae pv. tomato
SOURCE: M. Schroth
DISEASE: Bacterial speck
HOST: Tomato
Infection of flowers, peduncles, and stems.
Bacterial speck | Tomato
DISEASE: Bacterial speck
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas syringae pv. tomato
SOURCE: D. Cupples
DISEASE: Bacterial speck
HOST: Tomato
Field view of severely diseased plants.
Bacterial speck | Tomato
DISEASE: Bacterial speck
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas syringae pv. tomato
SOURCE: M. Schroth
DISEASE: Bacterial speck
HOST: Tomato
Green fruit with small, sunken, black lesions. Raised centers are surrounded by dark green halos.
Bacterial speck | Tomato
DISEASE: Bacterial speck
HOST: Tomato (Lycopersicon esculentum)
PATHOGEN: Pseudomonas syringae pv. tomato
SOURCE: S. Thomson