DISEASE: Bacterial leaf spot
HOST: Fern
Leaf with large, dark, longitudinal necrotic areas that differ from symptoms normally described for this disease.

Bacterial leaf spot | Fern
DISEASE: Bacterial leaf spot
HOST: Fern (Asplenium nidus)
PATHOGEN: Pseudomonas asplenii
SOURCE: R. Raabe
DISEASE: Sweet potato little leaf
HOST: Sweet potato
Infected plant (left) and healthy plant (right).

Sweet potato little leaf | Sweet potato
DISEASE: Sweet potato little leaf
HOST: Sweet potato (Ipomoea batatas)
PATHOGEN: 'Candidatus Phytoplasma aurantifolia'
PATHOGEN SYNONYM: Phytoplasma Peanut witches'-broom group
SOURCE: R. McCoy, M. Davis
DISEASE: Witches'-broom
HOST: Citrus (Lime)
Lime tree with compact, small leaves (witches'-broom). Leaves on older brooms dry out and eventually drop, leaving dead, bare branches. There are no flowers or fruit on brooms.

Witches'-broom | Citrus (Lime)
DISEASE: Witches'-broom
HOST: Citrus (Lime) (Citrus sp.)
PATHOGEN: 'Candidatus Phytoplasma aurantifolia'
PATHOGEN SYNONYM: Phytoplasma Peanut witches'-broom group
SOURCE: J. Bove, M. Garnier
DISEASE: Witches'-broom
HOST: Pigeon pea
Pigeon pea with witches'-broom.

Witches'-broom | Pigeon pea
DISEASE: Witches'-broom
HOST: Pigeon pea (Cajanus cajan)
PATHOGEN: 'Candidatus Phytoplasma aurantifolia'
PATHOGEN SYNONYM: Phytoplasma Peanut witches'-broom group
SOURCE: R. McCoy, M. Davis
DISEASE: Xanthomonas leaf blight
HOST: Onion
This was the first photo of onion leaf blight, which was considered a controversial finding for 10 years until an outbreak occurred in the West Indies.

Xanthomonas leaf blight | Onion
DISEASE: Xanthomonas leaf blight
HOST: Onion (Allium cepa)
PATHOGEN: Xanthomonas axonopodis pv. allii
PATHOGEN SYNONYM: Xanthomonas campestris pv. allii
SOURCE: A. Alvarez
DISEASE: Xanthomonas leaf blight
HOST: Onion
Diseased leaf with necrotic internal tissues.

Xanthomonas leaf blight | Onion
DISEASE: Xanthomonas leaf blight
HOST: Onion (Allium cepa)
PATHOGEN: Xanthomonas axonopodis pv. allii
PATHOGEN SYNONYM: Xanthomonas campestris pv. allii
SOURCE: A. Alvarez
DISEASE: Xanthomonas leaf blight
HOST: Onion
Onions with brown, necrotic, blighted leaves.

Xanthomonas leaf blight | Onion
DISEASE: Xanthomonas leaf blight
HOST: Onion (Allium cepa)
PATHOGEN: Xanthomonas axonopodis pv. allii
PATHOGEN SYNONYM: Xanthomonas campestris pv. allii
SOURCE: H. Schwartz
DISEASE: Xanthomonas leaf blight
HOST: Onion
Onions with severely blighted leaves.

Xanthomonas leaf blight | Onion
DISEASE: Xanthomonas leaf blight
HOST: Onion (Allium cepa)
PATHOGEN: Xanthomonas axonopodis pv. allii
PATHOGEN SYNONYM: Xanthomonas campestris pv. allii
SOURCE: H. Schwartz