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: Elm
Leaf with small, dark brown lesions and necrosis along veins.

Bacterial leaf spot | Elm
DISEASE: Bacterial leaf spot
HOST: Elm (Ulmus americana)
PATHOGEN: Pseudomonas syringae pv. ulmi
SOURCE: W. Sinclair
DISEASE: Bacterial wilt
HOST: Carnation
Carnation stem with cankers and cracks. Yellow sticky bacterial slime is often seen.

Bacterial wilt | Carnation
DISEASE: Bacterial wilt
HOST: Carnation (Dianthus caryophyllus)
PATHOGEN: Burkholderia caryophylli
PATHOGEN SYNONYM: Pseudomonas caryophylli
SOURCE: E. Hellmers, Royal Veterinary & Agricultural University
DISEASE: Bacterial wilt
HOST: Carnation
Severely diseased and withered plants.

Bacterial wilt | Carnation
DISEASE: Bacterial wilt
HOST: Carnation (Dianthus caryophyllus)
PATHOGEN: Burkholderia caryophylli
PATHOGEN SYNONYM: Pseudomonas caryophylli
SOURCE: T. Saito, M. Goto
DISEASE: Bacterial wilt
HOST: Carnation
Sliced stem with discolored vascular bundles.

Bacterial wilt | Carnation
DISEASE: Bacterial wilt
HOST: Carnation (Dianthus caryophyllus)
PATHOGEN: Burkholderia caryophylli
PATHOGEN SYNONYM: Pseudomonas caryophylli
SOURCE: T. Saito, M. Goto
DISEASE: Bacterial wilt
HOST: Carnation
Systemic infection caused cracking and necrosis of the stem.

Bacterial wilt | Carnation
DISEASE: Bacterial wilt
HOST: Carnation (Dianthus caryophyllus)
PATHOGEN: Burkholderia caryophylli
PATHOGEN SYNONYM: Pseudomonas caryophylli
SOURCE: R. Raabe
DISEASE: Elm leaf scorch
HOST: Elm
Diseased tree with scorch at leaf margins.

Elm leaf scorch | Elm
DISEASE: Elm leaf scorch
HOST: Elm (Ulmus americana)
PATHOGEN: Xylella fastidiosa
SOURCE: J. Sherald, M. Shurtleff
DISEASE: Elm leaf scorch
HOST: Elm
Severely diseased tree with dieback and scorched leaves.

Elm leaf scorch | Elm
DISEASE: Elm leaf scorch
HOST: Elm (Ulmus americana)
PATHOGEN: Xylella fastidiosa
SOURCE: W. Sinclair
DISEASE: Elm yellows
HOST: Elm
Symptoms of elm yellows occasionally appear on one branch before others, but more often they involve the entire crown.

Elm yellows | Elm
DISEASE: Elm yellows
HOST: Elm (Ulmus americana)
PATHOGEN: 'Candidatus Phytoplasma ulmi'
PATHOGEN SYNONYM: Phytoplasma Elm yellows group
SOURCE: W. Sinclair