DISEASE: Citrus greening (Huanglongbing)
HOST: Citrus (Mandarin orange)
The bacterium invades the tree slowly, leading to yellowing of the entire canopy. Pale yellow, blotchy mottled leaves are reduced in size.

Citrus greening (Huanglongbing) | Citrus (Mandarin orange)
DISEASE: Citrus greening (Huanglongbing)
HOST: Citrus (Mandarin orange) (Citrus reticulata)
PATHOGEN: 'Candidatus Liberibacter asiaticus'
PATHOGEN SYNONYM: Candidatus Liberobacter asiaticus
SOURCE: S. M. Garnsey
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: Halo blight
HOST: Bean
Leaf of 'Bountiful' bean with chlorotic halos, an early stage of disease. Tiny water-soaked are difficult to see.

Halo blight | Bean
DISEASE: Halo blight
HOST: Bean (Phaseolus vulgaris 'Bountiful')
PATHOGEN: Pseudomonas syringae pv. phaseolicola
PATHOGEN SYNONYM: Pseudomonas savastanoi pv. phaseolicola
SOURCE: M. Schroth