Symptoms on pumpkin
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Note the distinct interveinal chlorosis (yellowing), with the main leaf
veins remaining dark green in color. The interveinal tissue eventually
becomes necrotic (brown in color). The image on the right is drought damage.
Note the lack of the signature interveinal yellowing and green veins.
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| Interveinal chlorosis and necrosis on
pumpkin leaves |
Drought symptoms |
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Plants often exhibit shortened, tufted leaf growth that turns pale yellow
with necrosis on the leaf margins, resembling herbicide damage or Phytoplasma-like
symptoms. The stunted growth habit may be the main signature feature of
plants infected at the seedling stage, or may appear at individual notes
of older vines.
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| Stunted, tufted growth at nodes of pumpkin
plants |
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As the disease progresses one or two vines may wilt and collapse. Such
plants may support one or possibly two fruits, but they fail to reach
quality size and color. Finally, plants may become necrotic, rot, and
die if they were infected in early growth stages.
Click on Photos for Magnification
and Description
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| Wilted vines |
Poor fruit on infected plant |
Necrotic, rotting plant |
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Symptoms on summer squash
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Summer squash exhibits some of the same "signatures" as pumpkin, including
interveinal chlorosis and necrosis, but not tufted growth because plants
are not vining.
Click on Photos for Magnification
and Description
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| General chlorosis and collapse |
Interveinal chlorosis & necrosis not as distinct |
Plugging of xylem vessels |
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Symptoms on melons and cucumber
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The typical bacterial wilt symptoms on cucumber and melon consist of flaccid
(limp) leaves and then death of one or more vines. Cucumber and melon are
generally considered more susceptible than pumpkin and squash.
Click on Photos for Magnification
and Description |
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| Wilting melon plant |
Melon |
Cucumber |
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