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 stem and root rot
HOST: Sweet potato
Collapse of stems and roots caused by systemic activity of the pathogen.

Bacterial stem and root rot | Sweet potato
DISEASE: Bacterial stem and root rot
HOST: Sweet potato (Ipomoea batatas)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: N. Schaad
DISEASE: Bacterial stem and root rot
HOST: Sweet potato
Rot and collapse of stem, petioles, and leaves caused by systemic infection.

Bacterial stem and root rot | Sweet potato
DISEASE: Bacterial stem and root rot
HOST: Sweet potato (Ipomoea batatas)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: N. Schaad
DISEASE: Bacterial stem and root rot
HOST: Sweet potato
Rot and internal discoloration of tuber.

Bacterial stem and root rot | Sweet potato
DISEASE: Bacterial stem and root rot
HOST: Sweet potato (Ipomoea batatas)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: C. Clark
DISEASE: Phytoplasma disease
HOST: Armeria
Phytoplasma-infected armeria (left and right) compared with healthy plant (center).

Phytoplasma disease | Armeria
DISEASE: Phytoplasma disease
HOST: Armeria (Armeria maritima)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: R. Raabe
DISEASE: Phytoplasma disease
HOST: Daffodil
Phytoplasma disease of daffodil. Healthy (right).

Phytoplasma disease | Daffodil
DISEASE: Phytoplasma disease
HOST: Daffodil (Narcissus pseudonarcissus)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: R. Raabe
DISEASE: Phytoplasma disease
HOST: Gayfeather
Gayfeather with phyllody of flowers.

Phytoplasma disease | Gayfeather
DISEASE: Phytoplasma disease
HOST: Gayfeather (Liatris sp.)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Raabe