As its name suggests, bacterial wilt is a bacterial disease affecting cucurbits, such as:
Watermelons are rarely affected by bacterial wilt.
Note that bacterial wilt of cucurbits is different than the various bacteria-caused wilt diseases of corn. These corn diseases are caused by different organisms and spread by different insect pests.
Bacterial wilt of cucurbits typically cannot survive or spread without the assistance of cucumber beetles. Erwinia tracheiphila bacteria spend the winter in the digestive systems of the beetles and are then transferred from plant to plant as the insects feed during the growing season. The bacteria take up residence in the xylem, or water transport tissue of the plant, and block up the flow of moisture. Once a plant begins to succumb to bacterial wilt, it attracts more cucumber beetles. The cucumber beetles then ingest more bacteria, and the cycle continues.
- Rapid wilting.
- Sudden drying out.
- Pale, streaked leaves.
- Excessive branching.
- Whitish strings of bacterial slime oozing from stems when cut.
- Excessive flowering.
There is no cure for bacterial wilt. Remove and destroy affected plants immediately.
If bacterial wilt is a problem in your garden, choose resistant varieties when possible. Unfortunately, no muskmelon varieties have been shown to resist bacterial wilt.
Because the bacteria involved are dependent on cucumber beetles for survival, any measures taken to control the beetles will greatly reduce the risk of the disease:
- Till plant debris under in the fall to destroy insect shelter.
- Rotate garden crops.
- Deter cucumber beetles with floating row covers.
- Kill cucumber beetles using handpicking, natural predators, or natural or chemical insecticides.