DISEASE: Bacterial leaf spot
HOST: Cowpea
Leaf spots vary in size from small to large and some fall out in time, leaving a shot-hole appearance.

Bacterial leaf spot | Cowpea
DISEASE: Bacterial leaf spot
HOST: Cowpea (Vigna unguiculata)
PATHOGEN: Xanthomonas axonopodis pv. vignicola
PATHOGEN SYNONYM: Xanthomonas campestris pv. vignicola
SOURCE: R. Gitaitis
DISEASE: Bacterial leaf spot
HOST: Cowpea
Leaves with large, light brown necrotic areas.

Bacterial leaf spot | Cowpea
DISEASE: Bacterial leaf spot
HOST: Cowpea (Vigna unguiculata)
PATHOGEN: Xanthomonas axonopodis pv. vignicola
PATHOGEN SYNONYM: Xanthomonas campestris pv. vignicola
SOURCE: R. Gitaitis
DISEASE: Elm yellows
HOST: Elm
Symptoms of elm yellows occasionally appear on one branch before others, but more often they involve the entire crown.

Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus americana)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair
DISEASE: Elm yellows
HOST: Elm
Diseased twig (right) with epinasty, chlorosis, and yellowing of leaves. Sometimes both yellow and green leaves occur on same branch. Healthy branch (left).

Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus americana)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair
DISEASE: Elm yellows
HOST: Elm
Branches with butterscotch discoloration (center) and necrotic flecks in phloem and vascular cambium (right). Healthy branch (left). Sudden wilt and browning is common with small trees.

Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus americana)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair
DISEASE: Elm yellows
HOST: Elm
Elm yellows is characterized by witches'-brooms and stunting. Some cultivars have both yellow and reddish foliar discoloration.

Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus parvifolia)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair
DISEASE: Elm yellows
HOST: Elm
Late stage of elm yellows disease.

Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus rubra)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair
DISEASE: Goss's bacterial wilt and blight
HOST: Corn (Maize)
Wilted, dying plants. Leaves have gray to light yellow stripes and irregular margins that follow leaf veins. Systemically infected plants usually have orange vascular bundles.

Goss's bacterial wilt and blight | Corn (Maize)
DISEASE: Goss's bacterial wilt and blight
HOST: Corn (Maize) (Zea mays)
PATHOGEN: Clavibacter michiganensis subsp. nebraskensis
PATHOGEN SYNONYM: Corynebacterium nebraskense
SOURCE: A. Vidaver
DISEASE: Goss's bacterial wilt and blight
HOST: Corn (Maize)
The disease causes necrotic leaf lesions, which typically have dark flecks (freckles) within the lesions (not seen here).

Goss's bacterial wilt and blight | Corn (Maize)
DISEASE: Goss's bacterial wilt and blight
HOST: Corn (Maize) (Zea mays)
PATHOGEN: Clavibacter michiganensis subsp. nebraskensis
PATHOGEN SYNONYM: Corynebacterium nebraskense
SOURCE: A. Vidaver