RESULTS

(3)

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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: Elm yellows

HOST: Elm

Elm yellows is characterized by witches'-brooms and stunting. Some cultivars have both yellow and reddish foliar discoloration.

Elm yellows | Elm

DISEASE: Elm yellows

HOST: Elm (Ulmus parvifolia)

PATHOGEN: 'Candidatus Phytoplasma ulmi'

PATHOGEN SYNONYM: Phytoplasma Elm yellows group

SOURCE: W. Sinclair

DISEASE: Pseudomonas leaf spot

HOST: Primrose

Leaf with brownish red spots and reddening of adjacent areas. Disease begins as small, water-soaked lesions that later coalesce into large necrotic spots.

Pseudomonas leaf spot | Primrose

DISEASE: Pseudomonas leaf spot

HOST: Primrose (Primula sp.)

PATHOGEN: Pseudomonas syringae pv. primulae

SOURCE: APS