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: Fire blight
HOST: Pear
Blossom blight is first seen as water-soaked spots that rapidly turn brown to black as the disease becomes systemic and progresses down the shoot.

Fire blight | Pear
DISEASE: Fire blight
HOST: Pear (Pyrus communis)
PATHOGEN: Erwinia amylovora
SOURCE: S. Thomson
DISEASE: Witches'-broom
HOST: Paulownia (Empress tree)
Witches'-broom of paulownia.

Witches'-broom | Paulownia (Empress tree)
DISEASE: Witches'-broom
HOST: Paulownia (Empress tree) (Paulownia tomentosa)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: R. Davis, M. Davis