Tomato Diseases
Common Tomato Diseases and How to Treat Them
There are many tomato diseases that can affect both the leaves of the plant and/or the fruit. Most of these are weather-related, having to do with too much rain, too little rain, temperatures that are too hot or too cold, etc. Many diseases are spread by pests. Rarely are tomato diseases so severe that all plants and fruit are lost, but you can lessen any damage that occurs by buying disease-resistant plants and by careful inspection of your plants on a regular basis to catch anything that is happening before it spreads.
Let’s take a look at some of the more common tomato diseases:
Early Blight appears as dark spots on the stems, leaves or tomatoes. Some leaves may turn yellowish and die. This is a fungus which can be controlled by sulfur or copper sprays. Make sure you remove all infected plants and clean up the garden well in the fall, as Early Blight can survive the winter and re-infect your plants again next summer. Late Blight also affects both the leaves of the tomato plant and its fruit. It first appears as gray spots on the leaves, which can eventually be followed by white mold. The spots turn dry and the grayish areas can spread to the plant’s stem and fruit. Late Blight is a fungus and can be treated with fungicides. The disease can also spread to other members of the same plant family such as potatoes. It was, in fact, Late Blight that caused the Irish Potato Famine.
Southern Blight is a similar disease but the rings of white mold only appear on the stems of the tomato plants. It is a fungus that stops the plant from taking in the necessary nutrients, so it eventually discolors and dies. Research at Clemson University has shown that fertilizers with ammonium can help as can providing extra calcium. Gray Leaf Spot is one of the tomato diseases that attacks the plant’s leaves. Dark spots start to form and then turn grayish-brown. Eventually the center of these spots gets dry, cracks and falls out. Then leaves discolor and fall off. Fungicides can work to control the problem as can good weeding practices. Gray Leaf Spots usually form when the weather has been warm and moist.
One of the tomato diseases similar to Late Blight is Septoria Leaf spot. Dark, papery patches appear on the plant’s leaves. Copper sprays can help control this disease. Blossom end Rot is another one of the most common tomato diseases. The bottom of the tomato starts to turn dark and rots. It can be caused by too little calcium or too much nitrogen in the soil. Remove any infected tomatoes.
Today many tomato varieties are resistant to Verticillium Wilt, but if this fungus should appear in your garden, it may be tough to get rid of it. The fungus lives in the soil and can remain there for many years. It can also spread to many other kinds of vegetable plants. You will be able to notice yellowing and then browning of the veins in the plant leaves. It eventually discolors the stem and stops nutrients from getting to the plant and the plant dies. No chemical treatments are advised. Experts advise to plant resistant seeds and rotate crops.