There's nothing more discouraging to a tomato grower than to see a crop succumb to disease.
But tomatoes can be protected, according to Tom Stebbins, an agent with the Hamilton County University of Tennessee Extension office. Stebbins offers the following tips for problems common in our area.
1) Tomato wilts. Plants wilt and don't produce fruit even though there is enough moisture. This can be caused by virus or fungal pathogens. They can be transmitted in poor seed or from insects feeding in the greenhouse. Solutions: Buy from a good, clean nursery. Choose short, stocky plants. Leaves should not be yellow or mottled and should be free of insects.
2) Leaf spots and blights. Tomatoes get a number of fungal and bacterial leaf spots, which can lead to rot. Solutions: Keep the leaves as dry as possible by watering with a soaker hose. Good spacing and trellising also help keep leaves dry.
3) Fruit rots. Blossom-end rot causes a soft area on the bottom of the fruit. It is due to calcium deficiency in the fruit, not always in the soil. Lots of rain or a dry period can cause blossom-end rot. Heavy applications of nitrogen fertilizers or excessive potassium, magnesium, ammonium and sodium contribute to this problem. Solutions: Blossom-end rot can be minimized by maintaining uniform soil moisture. A good mulch of straw or pine needles around the plants keeps moisture balanced.
4) Distorted fruit/catfacing. Fruits are puckered and can have cavities extending deep into the flesh. With a good imagination, the fruit looks like a cat's face. Catfacing is the result of a disturbance to the flowers during fruit formation. The first clusters of tomatoes can often have this problem. Poor pollination also leads to abnormally shaped fruits. Another cause of catfacing is thought to be cold weather. Solutions: Avoid temperature extremes and setting out transplants too early in the season.
5) Fruit cracking. This is the result of rapid fruit growth brought on by plentiful rain, high temperatures and too much fertilizer. Solutions: Water weekly only if needed. Apply nitrogen fertilizers in lighter doses.