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Bacterial Wilt of Cucurbits
"Signature Symptoms"
Originally produced as a poster by T.A.Zitter and M.M. Kennelly
Department of Plant Pathology, Cornell University, Ithaca NY

Refer also to Cucumber Beetles, Corn Rootworms, and Bacterial Wilt in Cucurbit factsheet

Refer also to Life Cycle of Bacterial Wilt caused by Erwinia tracheiphila

Link to Photo Gallery of Bacterial Wilt of Cucurbits

Click on Photos below for Magnification and Description

Symptoms on pumpkin

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.


Interveinal Chlorosis #1 Interveinal Chlorosis #2 Drought Symptoms
Interveinal chlorosis and necrosis on pumpkin leaves Drought symptoms

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.


Stunted Pumpkin Plant #1 Stunted Pumpkin Plant #2 Stunted Pumpkin Plant #3
Stunted, tufted growth at nodes of pumpkin plants

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


Wilted Vines Poor Fruit Necrotic plant
Wilted vines Poor fruit on infected plant Necrotic, rotting plant

Symptoms on summer squash

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


Chlorosis Interveinal Chlorosis Plugged Xylem vessels
General chlorosis and collapse Interveinal chlorosis & necrosis not as distinct Plugging of xylem vessels

Symptoms on melons and cucumber

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
Wilting plant Wilting Melon wilting Cucumber
Wilting melon plant Melon Cucumber

This factsheet is also available as a PDF file. (The PDF format requires Adobe Acrobat (TM) Reader Software to be viewed.The reader is free from Adobe.)

List of fact sheets on Cucurbit Diseases

For additional photos link to the Bacterial Wilt Photo Gallery

Choose a vegetable from the pull-down menu below to get a listing of Fact Sheets and Information Bulletins relating to that crop.

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