Insects and diseases along with dearth of adequate water can cause wilting. Hereis the lowdown - see whether some of these scenerios might fit your specific scenario:
Plants that are affected regularly recuperate in the evening or overnight. Slowly, but, the wilting becomes increasingly worse and many plants expire. Fusarium and Verticillium wilts are due to soil-borne fungi that infringe tomato plants through roots that were wounded. The fungi propagate into the water-conducting tissue (xylem) in the stalk and obstruct the stream of water to the leaves. Leaves of plants that are affected turns yellowish, then wilts and dies. Plants that die ought to be removed and destroyed. As the vascular wilt fungi may live in the ground for many years, crop rotation is of small value. Using resistant varieties is the most practical method for home gardeners to stop declines due to wilts. Immune varieties might become infected but many plants create and live an acceptable harvest. F and the letters V following the variety name in seed catalogs or on seed packages denote varieties which are resistant to Fusarium and Verticillium wilts. Wilt resistant tomato varieties that perform well in Iowa comprise Burpee VF, Better Boy, Jetstar, and Star.
The sources of juglone in the land contain living and decaying plant material. Juglone is leached by rain droplets from the buds, leaves, and twigs. Juglone is exuded by living roots into the surrounding ground. Usually, the best concentration of juglone in the land exists within the dripline of trees that are walnut. Nothing can be done to save juglone- tomato plants that were damaged. Just remove and destroy. Gardeners that have big walnut trees near their gardens should consider alternative sites. Beans, corn, onions, beets, and carrots are patient of juglone and may be put nearer to walnut trees supplied adequate sunshine is received by the region.
The larva (caterpillar) drills into the stem and tunnels in the stalk. (The entry hole is little and frequently hard to find). Affected plants frequently perish and wilt. Nevertheless, stalk borer damaged plants which are given great care may live. It's an early season pest that goes from tall grassy weeds and sometimes assaults potatoes, tomatoes, and peppers in the vegetable garden. More than ONE tomato plant may be damaged by an individual stalk borer. The adult is a grayish brown moth that is inconspicuous. Tomato plants that die ought to be pulled and destroyed. The stalk borer may be also killed by the destruction of the plants. Mowing or cutting tall weedy places around vegetable gardens might additionally help control the pest. Stalk borers cannot be efficiently controlled with insecticides commonly used for lawn treatment.
Deficiency of Water
Tomato plants need about 1 inch of water weekly. Plants may wilt when soils are dry, but will restore quickly when they can be watered. An exhaustive watering once per week during hot, dry weather ought to be adequate. Apply water right to the ground round the bottom of the plants using a soaker or garden hose.
Hope this info makes it possible to discover the reason for your tomato plant challenges.