DISEASE: Bacterial blight
HOST: Hazelnut
Diseased young tree with discoloration of the cambium. Dieback of young twigs and branches is characteristic. Other typical symptoms are bud and twig necrosis and small, angular or round, water-soaked leaf spots.
Bacterial blight | Hazelnut
DISEASE: Bacterial blight
HOST: Hazelnut (Corylus americana)
PATHOGEN: Xanthomonas arboricola pv. corylina
SOURCE: J. Pscheidt
DISEASE: Chocolate spot
HOST: Corn (Maize)
Leaf with dark brown, elongated spots surrounded by broad, yellow halos.
Chocolate spot | Corn (Maize)
DISEASE: Chocolate spot
HOST: Corn (Maize) (Zea mays)
PATHOGEN: Pseudomonas syringae pv. coronafaciens
SOURCE: D. White
DISEASE: Halo blight
HOST: Oat
Oat leaves with oval lesions that darken in time and have distinctive yellow halos.
Halo blight | Oat
DISEASE: Halo blight
HOST: Oat (Avena sativa)
PATHOGEN: Pseudomonas syringae pv. coronafaciens
SOURCE: N. Schaad
DISEASE: Halo blight
HOST: Oat
Close-up of young and old lesions surrounded by halos.
Halo blight | Oat
DISEASE: Halo blight
HOST: Oat (Avena sativa)
PATHOGEN: Pseudomonas syringae pv. coronafaciens
SOURCE: N. Schaad
DISEASE: Multiplier disease
HOST: Strawberry
Multiplier disease causes production of numerous crowns along runners.
Multiplier disease | Strawberry
DISEASE: Multiplier disease
HOST: Strawberry (Fragaria × ananassa)
PATHOGEN: 'Candidatus Phytoplasma trifolii'
PATHOGEN SYNONYM: Phytoplasma Clover proliferation group
SOURCE: M. Clark
DISEASE: Witches'-broom
HOST: Alfalfa
Alfalfa plant (center) exhibiting stunting and proliferation of stems. Other symptoms are small, rounded, chlorotic, often puckered leaves and a yellowish cast.
Witches'-broom | Alfalfa
DISEASE: Witches'-broom
HOST: Alfalfa (Medicago sativa)
PATHOGEN: 'Candidatus Phytoplasma trifolii'
PATHOGEN SYNONYM: Phytoplasma Clover proliferation group
SOURCE: S. Thomson
DISEASE: Witches'-broom
HOST: Alfalfa
Young plant (left) with small, numerous stems (witches'-broom). Healthy stems (right).
Witches'-broom | Alfalfa
DISEASE: Witches'-broom
HOST: Alfalfa (Medicago sativa)
PATHOGEN: 'Candidatus Phytoplasma trifolii'
PATHOGEN SYNONYM: Phytoplasma Clover proliferation group
SOURCE: S. Thomson