There are a number of problems that can cause a tomato plant to wilt, some of which are readily alleviated and other that have no real solution. In some instances, a simple lack of water can cause the plant to wilt, meaning that giving the plant additional water is a suitable tomato wilt treatment. Other times, especially for some types of fungal wilt, increasing the pH of the soil can be effective. Bacterial wilt, which can occur under hot, moist conditions, sometimes cannot be treated at all, meaning the plants will have to be destroyed. Tomato wilt treatment for other causes of wilt — such as insects, nematodes in the soil or even surrounding trees — can vary but also can be very effective at restoring affected plants.
The difficultly in implementing certain tomato wilt treatment methods, as well as the lack of effective treatments for some types, emphasizes the fact that the best form of tomato wilt treatment in many cases is prevention. Tomato plants often come in varieties that have been specifically bred to be resistant to wilt, blight and other diseases that are common in different areas. If a tomato plant does not initially develop wilt, then there is no need for later treatment.
Increasing the pH of the soil can be an effective tomato wilt treatment when the source is fungal. There are several methods that can be used to increase the pH of the soil, but one of the more common ways is to add lime or wood ash to the soil. Increasing the amount of nitrogen that is available in the soil by using a fertilizer that is specifically higher in nitrogen than phosphorous or potassium can help prevent or treat fungal wilt, although it also might reduce the amount of fruit produced by the tomato plant.
If the plant is wilting because of pests, which usually are identified visually or by cutting open the stalks of the plant, then the best tomato wilt treatment is to physically remove the insects. Larger insects and some caterpillars and larvae are resistant to many non-industrial-grade pesticides and are best removed by hand. Smaller insects, such as whiteflies and aphids, usually can be treated by persistent washing of the plant with soap and water.
There are two situations in which tomato wilt treatment is guaranteed to be effective. The first when the plant is not receiving enough water, in which case increasing the frequency and amount of water provided in a day will quickly fix the problem. The second situation is when a tomato plant is near a walnut tree, which releases a harmful chemical from its roots. The solution here is to transplant the tomato plant away from the tree or, alternately, not to plant tomatoes near walnut trees in the first place.
There is no tomato wilt treatment in some instances. If a plant has verticillium wilt, for example, then the infected plant needs to be taken up and disposed of away from the rest of the garden. In a tightly packed garden, the wilt can spread quickly, meaning many of the plants might need to be removed. Long-term damage can be done, because the fungus or bacterium responsible for the infection often can overwinter deep in the soil, sometimes making a particular plot unusable for several years.