DISEASE: Bacterial black leaf spot
HOST: Clover
White clover with brown necrotic spots.

Bacterial black leaf spot | Clover
DISEASE: Bacterial black leaf spot
HOST: Clover (Trifolium repens)
PATHOGEN: Burkholderia andropogonis
PATHOGEN SYNONYM: Pseudomonas andropogonis
SOURCE: M. Goto
DISEASE: Bacterial black leaf spot
HOST: Clover
White clover leaves with brownish spots and some yellowing occurring at the margins.

Bacterial black leaf spot | Clover
DISEASE: Bacterial black leaf spot
HOST: Clover (Trifolium repens)
PATHOGEN: Burkholderia andropogonis
PATHOGEN SYNONYM: Pseudomonas andropogonis
SOURCE: R. Gitaitis
DISEASE: Hairy root
HOST: Rose
Hairy root symptoms of many fibrous roots (right). Noninfected root (left).

Hairy root | Rose
DISEASE: Hairy root
HOST: Rose (Rosa sp.)
PATHOGEN: Agrobacterium rhizogenes
SOURCE: R. Raabe
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: Hairy root
HOST: Rose
Crown gall (left) and hairy root (right) caused by Agrobacterium tumefaciens and A. rhizogenes, respectively. Healthy root (center).

Hairy root | Rose
DISEASE: Hairy root
HOST: Rose (Rosa sp.)
PATHOGEN: Agrobacterium rhizogenes
PATHOGEN SYNONYM: Rhizobium sp.
SOURCE: M. Schroth
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