Tomatoes are one of the most popular vegetables grown today. Unfortunately, they are also susceptible to a variety of problems, and can be killed by lack of nutrition, disease, fungi and insects, not to mention overlooking general care needs. Because the leaves on tomato plants can wilt from a number of causes, it is important to identify the symptoms before treating the tomato plant leaves.
Tomatoes need about 1 inch of water per week. Dry soil will cause the plant to wilt, but over-watering and watering the tomato plants from overhead can cause many diseases. One of the causes of tomato leaf roll is over-watering. The leaves will curl and wilt. Septoria leaf spot is also caused by over-watering when temperatures are warm, and can be treated with chlorothalonil and benomyl, according to Texas A&M University.
Fusarium wilt causes extensive root decay and death. Symptoms include yellowing, wilting, and the death of lower and younger leaves. If the stem is cut, there will be brown inside the stem, and the brown also may be seen on the roots and leaves. The plant may die, but if it survives, it will be a much smaller plant than a healthy one. Verticillium wilt is a similar disease, but the areas between the veins on the leaves are yellowed and wilting.
Insects & Planting Environment
If the tomato plant is wilting and has yellow, greenish-red or white specks on the plant, it could be infected by insects, such as leaf-footed bugs, stinkbugs, aphids, mealybugs, and spider mites. Bugs can be treated with insecticide spray every seven to 10 days. If bugs are present, sulphur dust, malathion or kelthane may also be used to eliminate the bugs. A home remedy for getting rid of bugs includes a mixture of dish washing liquid and water sprayed onto the plant. Introducing ladybirds can also eliminate many tomato pests. Tomato plants should not be planted near walnut or butternut trees. Both trees will cause wilt and discolouration and wilting from the toxic juglone that walnuts and butternuts leak into the soil. It will take several years for this toxin to leave the soil after a butternut or walnut tree is removed from the area, because the toxin is released from the roots.
If the roots of the tomato plant are swelling or knotting, the plant may be affected by root knot nematodes. This restricts the nutrients and results in yellowing and wilting leaves. Planting marigolds near the tomato, in the same soil, will eliminate this disease. Shredding and tilling cereal rye into the soil will also eliminate root knot.
In order to keep a tomato plant healthy, make sure the soil is full of organic materials, use varieties that are disease resistant, get rid of any weeds that can take away nutrients, water and fertilise each variety as directed, keep a clean garden area, eliminate all waste, watch for any insects, space your plants for good circulation, and rotate the crops so the same soil is not used each year for tomatoes. Remove any plants that are affected by any of any these problems, and avoid planting in soil that infected plants have been planted in. Be sure not to overwater or over-fertilise the tomato plants.