Tomato Bacterial Wilt

Bacterial Wilt is caused by the pathogen bacterium Ralstonia Solanacearum and is quite common in the moist sandy soils of the humid coastal south. This bacterium lives in the soil and will work its way quickly through the roots and up the stem of the plants.

Bacterial wilt often happens where plants have been cut, injured or weakened by insects or simply by cultivation. The bacterium clogs up the stem, preventing water and nutrients from reaching the leaves and the plant dies.

Causes and Symptoms

The first symptoms are wilting of the youngest leaves, usually during the hottest part of the day. This can easily go unnoticed because the leaves stay green but eventually the entire plant wilts and dies. These dramatic symptoms occur when the weather is hot (over 85 degrees), the humidity is high and lots of rainfall has left the ground wet. It’s also more common in soil with a high PH.

You can diagnose bacterial wilt by cutting the stem at the base of the plant. Look for discolored tissue. Suspend the stem in a glass of water. If it is infected, a white, slimy substance will ooze into the water within just a few minutes.

Treatment and control

There are no effective chemical controls. When the plants die, the pathogen is released into the soil, so it’s imperative that you remove diseased plants immediately. Do not compost the diseased plants!

So how do you prevent bacterial wilt? Good cultural controls are best.

  1. Running water can spread the disease to other parts of the garden so rotate your crops regularly away from host plants which could include all of the nightshades (tomatoes, peppers and eggplants), flowers including sunflowers and cosmos and potatoes.
  2. Try raised beds to improve drainage and control root knot nematodes that weaken plants, leaving them more susceptible to disease.
  3. Space plants far enough apart to provide good air circulation.
  4. Have your soil tested and maintain a pH of 6.2-6.5, which is ideal for growing tomatoes and many other vegetables.
  5. Wash your hands after handling infected plants and sterilize any gardening tool that could have been used in infected soil.

If you have ongoing problems with this or other soil borne disease, you may want to try raising your tomatoes in pots using commercial growing mix. You invest a ton of time and money into growing beautiful tomatoes; don’t let bacterial wilt ruin all of your efforts!

Have you dealt with bacterial wilt? If so, we’d love to hear from you in the comments section below.

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