DISEASE: Aster yellows
HOST: Onion
Infected plants with yellowish, malformed leaves.
Aster yellows | Onion
DISEASE: Aster yellows
HOST: Onion (Allium cepa)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Rowe
DISEASE: Aster yellows
HOST: Onion
Onion flower with unusual symptoms (left) compared with healthy inflorescence (right). Flowers are distorted and often have abnormally long pedicels. Young leaves may have yellow streaks or a general yellowing of basal portions.
Aster yellows | Onion
DISEASE: Aster yellows
HOST: Onion (Allium cepa)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Raabe
DISEASE: Bacterial blight
HOST: Pea
Pea pod with diseased seeds and infection along the suture.
Bacterial blight | Pea
DISEASE: Bacterial blight
HOST: Pea (Pisum sativum)
PATHOGEN: Pseudomonas syringae pv. pisi
SOURCE: J. M. Kraft
DISEASE: Bacterial blight
HOST: Pea
Pea plant with water-soaked lesions on stems and leaves with some bacterial exudate evident. Irregular lesions turn dark brown with light tan centers. Severe distortion of stems, petioles, and growing points may occur.
Bacterial blight | Pea
DISEASE: Bacterial blight
HOST: Pea (Pisum sativum)
PATHOGEN: Pseudomonas syringae pv. pisi
SOURCE: S. Thomson
DISEASE: Bacterial blight
HOST: Pea
Dark lesions on pods and dorsal sutures.
Bacterial blight | Pea
DISEASE: Bacterial blight
HOST: Pea (Pisum sativum)
PATHOGEN: Pseudomonas syringae pv. pisi
SOURCE: J. Young
DISEASE: Bacterial blight
HOST: Pea
Severely diseased plant with array of blight symptoms.
Bacterial blight | Pea
DISEASE: Bacterial blight
HOST: Pea (Pisum sativum)
PATHOGEN: Pseudomonas syringae pv. pisi
SOURCE: J. Young
DISEASE: Bacterial blight
HOST: Pea
Leaves with typical blight symptoms. The disease also affects nodes, stipules, floral parts, stems, and pods.
Bacterial blight | Pea
DISEASE: Bacterial blight
HOST: Pea (Pisum sativum)
PATHOGEN: Pseudomonas syringae pv. pisi
SOURCE: M. Schroth
DISEASE: Bacterial decline
HOST: Papaya
Bacterial decline of papaya, historically called St. Croix decline, was thought to be caused by a fungus. This picture shows a papaya with dead top and side branches, a severe stage of the disease.
Bacterial decline | Papaya
DISEASE: Bacterial decline
HOST: Papaya (Carica papaya)
PATHOGEN: Erwinia papayae
SOURCE: M. Schroth
DISEASE: Bacterial decline
HOST: Papaya
Water-soaked papaya stem in St. Croix. Dark, water-soaked, greasy lesions occur on stems and leaves. The causal agent differs somewhat from descriptions of Erwinia papayae D strains in Micronesia.
Bacterial decline | Papaya
DISEASE: Bacterial decline
HOST: Papaya (Carica papaya)
PATHOGEN: Erwinia papayae
SOURCE: M. Schroth