How to Identify Tomato Wilt

Check tomato plants during the night for wilting, which is a symptom of verticillium wilt.

Tomato wilt is caused by fungal, bacterial, viral or nematode pathogens, according to the Alabama Cooperative Extension. Wilt diseases are soil-borne pathogens that enter plants through their root system either naturally during root growth or wounds. Generally, there is little gardeners can do for their infect tomato plants. Fungicides are unavailable for controlling wilt diseases. However, bacterial wilt may be controlled through fumigation. Diagnosing what type of wilt has infected your tomato crop is imperative for control and prevention.

Things You'll Need

• Soil thermometer
• Bypass shears
• Clear drinking glass

Instructions

1. Walk around your tomato plants looking for fallen leaves. Tomato plants infected with fusarium wilt prematurely drop their leaves.

2. Press a soil thermometer into the soil at a depth of 6 inches. Tomato plants are most commonly infected with fusarium wilt when soil temperatures are between 78 to 90 degrees Fahrenheit, and bacterial wilt may be the cause if soil temperatures are over 75 degrees Fahrenheit. Also, verticillium wilt is likely the cause when temperatures are between 60 to 75 degrees Fahrenheit. Measure the soil temperature in the morning and afternoon. Take an average of both temperature readings to obtain an accurate reading.

3. Cut off a piece of tomato stem and place in a clear cup of water. Tomato plant stems infected with bacterial wilt will ooze a white substance in water.

4. Examine tomatoes for signs of discoloration or rings, which suggests tomato spotted wilt virus. Plants infected with tomato spotted wilt virus may also display purple-brown streaks on stems and leaves.

5. Inspect your other vegetable crops. Bacterial wilt infects plants like potatoes, eggplants and peppers. Verticillium wilt attacks strawberries, okras, peppers, potatoes, cucumbers, watermelons and radishes.

Tips & Warnings

• Remove and burn any diseased tomato plants from the garden area to prevent the spread of a wilt disease.

• Avoid replanting in wilt-diseased areas because wilt diseases such as verticillium wilt can live in the soil for decades.

References

• Cornell University Plant Pathology Department; Verticillium Wilt of Tomato; Arden Sherf
• Alabama Cooperative Extension: Wilt Diseases of Tomato