DISEASE: Alfalfa dwarf
HOST: Alfalfa
Alfalfa dwarf is characterized by stunted plants (left), usually dark blue-green in color. Xylem tissues become brown, especially when exposed to air.
Alfalfa dwarf | Alfalfa
DISEASE: Alfalfa dwarf
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Xylella fastidiosa
SOURCE: R. M. Davis
DISEASE: Bacterial flower stalk and leaf necrosis
HOST: Onion
Dark, rotted areas of stalk and leaves caused by systemic invasion of the pathogen.
Bacterial flower stalk and leaf necrosis | Onion
DISEASE: Bacterial flower stalk and leaf necrosis
HOST: Onion (Allium cepa)
PATHOGEN: Pseudomonas marginalis pv. marginalis
SOURCE: S. Mohan
DISEASE: Bacterial flower stalk and leaf necrosis
HOST: Onion
Gray-brown rot of onion after inoculation. Disease starts as small, water-soaked lesions that later develop into slimy, gray-brown rot. The disease progresses downward from the stalk and may rot the entire bulb.
Bacterial flower stalk and leaf necrosis | Onion
DISEASE: Bacterial flower stalk and leaf necrosis
HOST: Onion (Allium cepa)
PATHOGEN: Pseudomonas marginalis pv. marginalis
SOURCE: R. Gitaitis
DISEASE: Bacterial flower stalk and leaf necrosis
HOST: Onion
Leaves with necrosis and rot. The common name for this disease is the same as those used for two other diseases. Also, another common name for this disease is bacterial soft rot.
Bacterial flower stalk and leaf necrosis | Onion
DISEASE: Bacterial flower stalk and leaf necrosis
HOST: Onion (Allium cepa)
PATHOGEN: Pseudomonas marginalis pv. marginalis
SOURCE: S. Mohan
DISEASE: Lethal yellowing
HOST: Palm
Palm with dark necrotic inflorescence.
Lethal yellowing | Palm
DISEASE: Lethal yellowing
HOST: Palm (Cocos nucifera)
PATHOGEN: 'Candidatus Phytoplasma palmae'
PATHOGEN SYNONYM: Phytoplasma Coconut lethal yellowing group
SOURCE: N. A. Harrison
DISEASE: Lethal yellowing
HOST: Palm
Palm with close-up of diseased yellow spear leaf.
Lethal yellowing | Palm
DISEASE: Lethal yellowing
HOST: Palm (Cocos nucifera)
PATHOGEN: 'Candidatus Phytoplasma palmae'
PATHOGEN SYNONYM: Phytoplasma Coconut lethal yellowing group
SOURCE: W. Sinclair
DISEASE: Lethal yellowing
HOST: Palm
Progression of lethal yellowing symptoms. Older fronds of coconut palm turn yellow, followed by yellowing of younger ones near center of crown.
Lethal yellowing | Palm
DISEASE: Lethal yellowing
HOST: Palm (Cocos nucifera)
PATHOGEN: 'Candidatus Phytoplasma palmae'
PATHOGEN SYNONYM: Phytoplasma Coconut lethal yellowing group
SOURCE: W. Sinclair
DISEASE: Lethal yellowing
HOST: Palm
Coconut palm with yellowing and desiccation of leaves, late stage of disease.
Lethal yellowing | Palm
DISEASE: Lethal yellowing
HOST: Palm (Cocos nucifera)
PATHOGEN: 'Candidatus Phytoplasma palmae'
PATHOGEN SYNONYM: Phytoplasma Coconut lethal yellowing group
SOURCE: N. A. Harrison
DISEASE: Lethal yellowing
HOST: Palm
Palms near death, noted by yellow fronds, some that have dehisced.
Lethal yellowing | Palm
DISEASE: Lethal yellowing
HOST: Palm (Cocos nucifera)
PATHOGEN: 'Candidatus Phytoplasma palmae'
PATHOGEN SYNONYM: Phytoplasma Coconut lethal yellowing group
SOURCE: M. Davis