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: Peanut
The disease causes water-soaked lesions, particularly on upper leaf surfaces. Lesions enlarge and later display brown necrotic areas. Leaflets become chlorotic and shed prematurely.
Bacterial leaf spot | Peanut
DISEASE: Bacterial leaf spot
HOST: Peanut (Arachis hypogaea)
PATHOGEN: Pseudomonas sp.
SOURCE: P. Subrahmanyam
DISEASE: Bacterial wilt
HOST: Peanut
First sign of disease is slight drooping or curling of leaves. As the plant declines, foliage turns yellow, followed by wilt and death of stems.
Bacterial wilt | Peanut
DISEASE: Bacterial wilt
HOST: Peanut (Arachis hypogaea)
PATHOGEN: Ralstonia solanacearum
PATHOGEN SYNONYM: Pseudomonas solanacearum
SOURCE: D. Porter
DISEASE: Bacterial wilt
HOST: Peanut
Advanced stage of disease with death of plants.
Bacterial wilt | Peanut
DISEASE: Bacterial wilt
HOST: Peanut (Arachis hypogaea)
PATHOGEN: Ralstonia solanacearum
PATHOGEN SYNONYM: Pseudomonas solanacearum
SOURCE: D. Porter
DISEASE: Bacterial wilt
HOST: Peanut
Vascular discoloration of taproot.
Bacterial wilt | Peanut
DISEASE: Bacterial wilt
HOST: Peanut (Arachis hypogaea)
PATHOGEN: Ralstonia solanacearum
PATHOGEN SYNONYM: Pseudomonas solanacearum
SOURCE: APS
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: Coffee leaf scorch
HOST: Coffee
Diseased twig with yellowish, stunted leaves (left). Healthy twig with normal-sized leaves (right).
Coffee leaf scorch | Coffee
DISEASE: Coffee leaf scorch
HOST: Coffee (Coffea arabica)
PATHOGEN: Xylella fastidiosa
SOURCE: S. Purcell
DISEASE: Halo blight
HOST: Coffee
Leaf with blackish lesions surrounded by yellow halos.
Halo blight | Coffee
DISEASE: Halo blight
HOST: Coffee (Coffea dewevrei)
PATHOGEN: Pseudomonas syringae pv. garcae
SOURCE: S. Mohan
DISEASE: Halo blight
HOST: Coffee
Young blighted coffee plant.
Halo blight | Coffee
DISEASE: Halo blight
HOST: Coffee (Coffea dewevrei)
PATHOGEN: Pseudomonas syringae pv. garcae
SOURCE: S. Mohan