DISEASE: Fire blight
HOST: Apple
Canker on trunk oozing fire blight bacteria.

Fire blight | Apple
DISEASE: Fire blight
HOST: Apple (Malus domestica)
PATHOGEN: Erwinia amylovora
SOURCE: S. Thomson
DISEASE: Hairy root
HOST: Apple
Crown gall (left) and hairy root (right) caused by Agrobacterium tumefaciens and A. rhizogenes, respectively.

Hairy root | Apple
DISEASE: Hairy root
HOST: Apple (Malus domestica)
PATHOGEN: Agrobacterium rhizogenes
PATHOGEN SYNONYM: Rhizobium sp.
SOURCE: APS
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