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: Bacterial black spot
HOST: Mango
Mango fruit with oozing lesion (A) and raised, black lesions (B).

Bacterial black spot | Mango
DISEASE: Bacterial black spot
HOST: Mango (Mangifera indica)
PATHOGEN: Xanthomonas campestris pv. mangiferaeindicae
SOURCE: R. Ploetz
DISEASE: Bacterial black spot
HOST: Mango
Mango branch with cankers.

Bacterial black spot | Mango
DISEASE: Bacterial black spot
HOST: Mango (Mangifera indica)
PATHOGEN: Xanthomonas campestris pv. mangiferaeindicae
SOURCE: R. Ploetz
DISEASE: Bacterial black spot
HOST: Mango
Leaf with blackish spots delimited by veins.

Bacterial black spot | Mango
DISEASE: Bacterial black spot
HOST: Mango (Mangifera indica)
PATHOGEN: Xanthomonas campestris pv. mangiferaeindicae
SOURCE: APS
DISEASE: Bacterial black spot
HOST: Mango
Stem and leaf with black necroses.

Bacterial black spot | Mango
DISEASE: Bacterial black spot
HOST: Mango (Mangifera indica)
PATHOGEN: Xanthomonas campestris pv. mangiferaeindicae
SOURCE: APS
DISEASE: Bacterial black spot
HOST: Mango
Oozing cankers on young stem.

Bacterial black spot | Mango
DISEASE: Bacterial black spot
HOST: Mango (Mangifera indica)
PATHOGEN: Xanthomonas campestris pv. mangiferaeindicae
SOURCE: APS
DISEASE: Bacterial leaf spot (Head rot)
HOST: Lettuce
Leaf with black, greasy spots that tend to be vein delimited. Lesions begin as small, angular, water-soaked lesions that coalesce, resulting in large necrotic areas.

Bacterial leaf spot (Head rot) | Lettuce
DISEASE: Bacterial leaf spot (Head rot)
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Xanthomonas axonopodis pv. vitians
PATHOGEN SYNONYM: Xanthomonas campestris pv. vitians
SOURCE: A. Alvarez
DISEASE: Bacterial wilt
HOST: Squash
Field with severe symptoms of wilt. Foliage often is chlorotic and leaf margins may be chlorotic and necrotic before plant death. Bacterial ooze may be seen streaming from the xylem when infected stems are cut.

Bacterial wilt | Squash
DISEASE: Bacterial wilt
HOST: Squash (Cucurbita maxima)
PATHOGEN: Erwinia tracheiphila
SOURCE: B. Jacobsen, M. Shurtleff
DISEASE: Corky root
HOST: Lettuce
Corky root causes a reduction in size of lettuce heads and root systems; susceptible cultivar (right) and resistant cultivar (left).

Corky root | Lettuce
DISEASE: Corky root
HOST: Lettuce (Lactuca sativa)
PATHOGEN: Sphingomonas suberifaciens
PATHOGEN SYNONYM: Rhizomonas suberifaciens
SOURCE: E. J. Ryder