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: Australian citrus dieback
HOST: Citrus (Lime)
Severe decline, a late stage of disease. The disease spreads slowly in mature trees, progressing faster in young trees.

Australian citrus dieback | Citrus (Lime)
DISEASE: Australian citrus dieback
HOST: Citrus (Lime) (Citrus sp.)
PATHOGEN: 'Candidatus Phytoplasma australiense'
PATHOGEN SYNONYM: Phytoplasma Stolbur group
SOURCE: P. Broadbent
DISEASE: Bacterial blast and black pit
HOST: Citrus (Lime)
Characteristic symptoms of brownish black lesions on twigs and leaves (blast), starting with infection of petioles. Black pit refers to brown to black sunken spots on fruit, 5 to 20 mm in diameter.

Bacterial blast and black pit | Citrus (Lime)
DISEASE: Bacterial blast and black pit
HOST: Citrus (Lime) (Citrus sp.)
PATHOGEN: Pseudomonas syringae pv. syringae
SOURCE: P. Broadbent
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple
Infected leaf with olive green, puffy appearance.

Bacterial heart rot and fruit collapse | Pineapple
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple (Ananas comosus)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: G. Taniguchi
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple
Advanced stage of heart rot. Note puffy appearance of discolored midportions of central heart leaves.

Bacterial heart rot and fruit collapse | Pineapple
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple (Ananas comosus)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: C. V. Subere
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple
Dark, necrotic, decayed area at bases of central heart leaves. Advanced stage is characterized by an olive green leaf color and puffy appearance of midportions of leaves.

Bacterial heart rot and fruit collapse | Pineapple
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple (Ananas comosus)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: K. Rohrbach
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple
Diseased plant with reddening of leaves, a symptom of the disease.

Bacterial heart rot and fruit collapse | Pineapple
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple (Ananas comosus)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: G. Taniguchi
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple
Diseased pineapple (right) has olive green color. Healthy fruit (left).

Bacterial heart rot and fruit collapse | Pineapple
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple (Ananas comosus)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: K. Rohrbach
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple
Diseased ripe fruit with external discoloration.

Bacterial heart rot and fruit collapse | Pineapple
DISEASE: Bacterial heart rot and fruit collapse
HOST: Pineapple (Ananas comosus)
PATHOGEN: Dickeya sp.
PATHOGEN SYNONYM: Erwinia chrysanthemi
SOURCE: C. V. Subere