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 leaf spot
HOST: Larkspur
Infected leaflets with many purplish spots with necrotic centers.

Bacterial leaf spot | Larkspur
DISEASE: Bacterial leaf spot
HOST: Larkspur (Delphinium sp.)
PATHOGEN: Pseudomonas syringae pv. delphinii
SOURCE: R. Raabe
DISEASE: Fire blight
HOST: Pluot
Fire blight cankers on major limb. Pluot is an interspecific hybrid of plum and apricot.

Fire blight | Pluot
DISEASE: Fire blight
HOST: Pluot (Prunus hybrid 'Dandy Dapple')
PATHOGEN: Erwinia amylovora
SOURCE: S. Mohan
DISEASE: Fire blight
HOST: Pluot
Dead shoot, the result of systemic infection.

Fire blight | Pluot
DISEASE: Fire blight
HOST: Pluot (Prunus hybrid 'Dandy Dapple')
PATHOGEN: Erwinia amylovora
SOURCE: S. Mohan
DISEASE: Fire blight
HOST: Pluot
Typical symptoms of fire blight-infected shoot.

Fire blight | Pluot
DISEASE: Fire blight
HOST: Pluot (Prunus hybrid 'Dandy Dapple')
PATHOGEN: Erwinia amylovora
SOURCE: S. Mohan
DISEASE: Larkspur virescence
HOST: Larkspur
Two diseased plants with stunted and small leaves, lack of flower coloration, and bunched flower buds. Healthy plant (left).

Larkspur virescence | Larkspur
DISEASE: Larkspur virescence
HOST: Larkspur (Delphinium sp.)
PATHOGEN: 'Candidatus Phytoplasma asteris'
PATHOGEN SYNONYM: Phytoplasma Aster yellows group
SOURCE: R. Raabe