DISEASE: European stone fruit yellows
HOST: Almond
The disease causes yellowing and rolling of leaves (right). Leaves become thick and rough in texture. Healthy leaves (left).

European stone fruit yellows | Almond
DISEASE: European stone fruit yellows
HOST: Almond (Prunus dulcis)
PATHOGEN: 'Candidatus Phytoplasma prunorum'
PATHOGEN SYNONYM: Phytoplasma Apple proliferation group
SOURCE: E. Seemueller
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: Western wetwood
HOST: Elm
Spokelike, discolored extensions that expanded into sapwood, following an injection with a fungicide. The causal agent is not known but symptoms are associated with bacteria and yeast.

Western wetwood | Elm
DISEASE: Western wetwood
HOST: Elm (Ulmus americana)
PATHOGEN: Causal agent unknown
SOURCE: W. Sinclair