DISEASE: Greasy center
HOST: Poinsettia
Stem with dark cankers and copious ooze. Necrotic areas are greasy in appearance and eventually turn light tan to brown with a papery texture as the cuticle becomes detached.
Greasy center | Poinsettia
DISEASE: Greasy center
HOST: Poinsettia (Euphorbia pulcherrima)
PATHOGEN: Pseudomonas viridiflava
SOURCE: R. Raabe
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
DISEASE: Lethal yellowing/scorch
HOST: Beet
Blue-green sharpshooter (Graphocephala atropunctata) transmits Xylella fastidiosa and has a large host range, including palms, grasses, and grapes.
Lethal yellowing/scorch | Beet
DISEASE: Lethal yellowing/scorch
HOST: Beet (Beta vulgaris)
PATHOGEN: Xylella fastidiosa
SOURCE: A. Purcell, M. Davis