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: 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
DISEASE: Bacterial decline
HOST: Papaya
Bacterial invasion of leaf veins and adjacent tissues of papaya in Micronesia. This disease has also been called canker, dieback, and blight.
Bacterial decline | Papaya
DISEASE: Bacterial decline
HOST: Papaya (Carica papaya)
PATHOGEN: Erwinia papayae
SOURCE: E. Trujillo
DISEASE: Bacterial decline
HOST: Papaya
Complete destruction of papaya plantation in Micronesia. Only a severely damaged trunk remains.
Bacterial decline | Papaya
DISEASE: Bacterial decline
HOST: Papaya (Carica papaya)
PATHOGEN: Erwinia papayae
SOURCE: E. Trujillo
DISEASE: Bacterial fasciation
HOST: Papaya
Fasciation symptoms of papaya. Causal agent is unknown.
Bacterial fasciation | Papaya
DISEASE: Bacterial fasciation
HOST: Papaya (Carica papaya)
PATHOGEN: Causal agent unknown
SOURCE: A. Alvarez
DISEASE: Bacterial leaf blight
HOST: Wheat
Diseased leaves with whitish blotches. Initial water-soaked spots become necrotic and progress from gray-green to tannish white.
Bacterial leaf blight | Wheat
DISEASE: Bacterial leaf blight
HOST: Wheat (Triticum aestivum)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: J. Otta
DISEASE: Bacterial leaf blight
HOST: Wheat
Diseased leaves with whitish blotches. The disease begins as water-soaked spots and then become necrotic and progresses from gray-green to tannish white.
Bacterial leaf blight | Wheat
DISEASE: Bacterial leaf blight
HOST: Wheat (Triticum aestivum)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: L. Claflin
DISEASE: Bacterial leaf blight
HOST: Wheat
Leaves with reddish tan necrotic lesions.
Bacterial leaf blight | Wheat
DISEASE: Bacterial leaf blight
HOST: Wheat (Triticum aestivum)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: L. Claflin