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: Olive knot
HOST: Olive
Multiple infections of young stems. The bacterium invades vascular tissues during certain times of the year and may be isolated from branches that appear healthy.
Olive knot | Olive
DISEASE: Olive knot
HOST: Olive (Olea europaea)
PATHOGEN: Pseudomonas savastanoi pv. savastanoi
SOURCE: M. Schroth
DISEASE: Olive knot
HOST: Olive
Tree with knots/galls on branches along with twig dieback, which is associated with knots. Fusarium and Diplodia spp. infect through knots and are thought to be main reason for dieback.
Olive knot | Olive
DISEASE: Olive knot
HOST: Olive (Olea europaea)
PATHOGEN: Pseudomonas savastanoi pv. savastanoi
SOURCE: M. Schroth
DISEASE: Olive knot
HOST: Olive
Multiple infections on olive branch. Knots at this stage begin to die from the outside in and are infected by several fungi.
Olive knot | Olive
DISEASE: Olive knot
HOST: Olive (Olea europaea)
PATHOGEN: Pseudomonas savastanoi pv. savastanoi
SOURCE: M. Schroth
DISEASE: Witches'-broom
HOST: Alfalfa
Alfalfa plant (center) exhibiting stunting and proliferation of stems. Other symptoms are small, rounded, chlorotic, often puckered leaves and a yellowish cast.
Witches'-broom | Alfalfa
DISEASE: Witches'-broom
HOST: Alfalfa (Medicago sativa)
PATHOGEN: 'Candidatus Phytoplasma trifolii'
PATHOGEN SYNONYM: Phytoplasma Clover proliferation group
SOURCE: S. Thomson
DISEASE: Witches'-broom
HOST: Alfalfa
Young plant (left) with small, numerous stems (witches'-broom). Healthy stems (right).
Witches'-broom | Alfalfa
DISEASE: Witches'-broom
HOST: Alfalfa (Medicago sativa)
PATHOGEN: 'Candidatus Phytoplasma trifolii'
PATHOGEN SYNONYM: Phytoplasma Clover proliferation group
SOURCE: S. Thomson
DISEASE: Witches'-broom
HOST: Cactus
Witches'-broom of Opuntia cactus.
Witches'-broom | Cactus
DISEASE: Witches'-broom
HOST: Cactus (Opuntia sp.)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: R. McCoy, M. Davis
DISEASE: Witches'-broom
HOST: Citrus (Lime)
Lime tree with compact, small leaves (witches'-broom). Leaves on older brooms dry out and eventually drop, leaving dead, bare branches. There are no flowers or fruit on brooms.
Witches'-broom | Citrus (Lime)
DISEASE: Witches'-broom
HOST: Citrus (Lime) (Citrus sp.)
PATHOGEN: 'Candidatus Phytoplasma aurantifolia'
PATHOGEN SYNONYM: Phytoplasma Peanut witches'-broom group
SOURCE: J. Bove, M. Garnier
DISEASE: Witches'-broom
HOST: Dogwood
Witches'-broom of eastern dogwood.
Witches'-broom | Dogwood
DISEASE: Witches'-broom
HOST: Dogwood (Cornus sp.)
PATHOGEN: 'Candidatus Phytoplasma' sp.
PATHOGEN SYNONYM: Phytoplasma (undefined)
SOURCE: W. Sinclair