DISEASE: Alfalfa dwarf
HOST: Alfalfa
Alfalfa dwarf is characterized by stunted plants (left), usually dark blue-green in color. Xylem tissues become brown, especially when exposed to air.

Alfalfa dwarf | Alfalfa
DISEASE: Alfalfa dwarf
HOST: Alfalfa (Medicago sativa)
PATHOGEN: Xylella fastidiosa
SOURCE: R. M. Davis
DISEASE: Almond leaf scorch
HOST: Almond
Light brown necrotic (scorched) areas on curling leaves.

Almond leaf scorch | Almond
DISEASE: Almond leaf scorch
HOST: Almond (Prunus dulcis)
PATHOGEN: Xylella fastidiosa
SOURCE: W. Sinclair
DISEASE: Almond leaf scorch
HOST: Almond
Dying almond trees with scorched appearance. Initial symptoms are marginal chlorosis, usually late in the year. Scorch often is first noted at leaf tips, symptoms worsen, and terminal branches may die.

Almond leaf scorch | Almond
DISEASE: Almond leaf scorch
HOST: Almond (Prunus dulcis)
PATHOGEN: Xylella fastidiosa
SOURCE: R. Davis, M. Davis
DISEASE: Angular leaf spot
HOST: Strawberry
Early stage of disease begins as water-soaked, angular lesions, often with yellow ooze. There also are blight and vascular collapse stages.

Angular leaf spot | Strawberry
DISEASE: Angular leaf spot
HOST: Strawberry (Fragaria × ananassa)
PATHOGEN: Xanthomonas fragariae
SOURCE: M. Schroth
DISEASE: Angular leaf spot
HOST: Strawberry
Advanced stage of disease with dry, brownish necrotic lesions on upper leaf surface.

Angular leaf spot | Strawberry
DISEASE: Angular leaf spot
HOST: Strawberry (Fragaria chiloensis)
PATHOGEN: Xanthomonas fragariae
SOURCE: A. Alvarez
DISEASE: Angular leaf spot
HOST: Strawberry
Diseased sepals.

Angular leaf spot | Strawberry
DISEASE: Angular leaf spot
HOST: Strawberry (Fragaria × ananassa)
PATHOGEN: Xanthomonas fragariae
SOURCE: M. Schroth
DISEASE: Angular leaf spot
HOST: Strawberry
Vascular collapse stage occurs from systemic invasion of crown region.

Angular leaf spot | Strawberry
DISEASE: Angular leaf spot
HOST: Strawberry (Fragaria × ananassa)
PATHOGEN: Xanthomonas fragariae
SOURCE: M. Schroth
DISEASE: Bacterial leaf scorch
HOST: Pecan
Pecan with necrotic scorched leaves with distinct dark lines between healthy and diseased tissues.

Bacterial leaf scorch | Pecan
DISEASE: Bacterial leaf scorch
HOST: Pecan (Carya illinoinensis)
PATHOGEN: Xylella fastidiosa
SOURCE: T. Brenneman