Squash Bacterial Wilt

Erwinia tracheiphila, a bacterium

Bacterial wilt on pumpkin
Bacterial wilt on pumpkin [Credit: Howard F. Schwartz, Colorado State University]
Bacterial wilt on melon foliage
Bacterial wilt on melon foliage [Credit: Edward Sikora, Auburn University, Bugwood.org]

Host Plants:

On Crops: Cucumbers, melons and occasionally squash. Bacterial wilt is transmitted by striped and spotted cucumber beetles.

Where Found:

North America, mostly east of the Rocky Mountains


Bacterial wilt usually strikes just as the plants develop vines. Individual leaf tips will suddenly begin to wilt, with the wilting becoming more extensive each day. Within a few days the vine dies, and other vines nearby show symptoms of infection. To diagnose bacterial wilt, cut off the wilting vine and squeeze the stem. Press your finger to the juice that comes out of the stem and slowly pull it away. If a thread of sticky white liquid comes out of the stem, the plant has bacterial wilt.


Promising plants can be quickly killed by bacterial wilt. The bacteria live on the mouthparts of cucumber beetles, so it only takes a few beetles to cause significant problems. Once they are infected, plants cannot recover from bacterial wilt.

Preventing Problems:

The best way to prevent this problem is to grow plants beneath floating row covers until they start to bloom and need to be visited by pollinating insects. Cucumber beetles can also be collected with a hand-held vacuum, and you can capture some in yellow pails filled with soapy water. Traps baited with pheromone lures are widely available. There are several resistant varieties, and non-bitter or 'burpless' cucumbers are non-preferred by cucumber beetles, so they are naturally resistant to this disease.

Managing Outbreaks:

Pull up infected plants and compost them.

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