Tomatoes are fairly easy to grow. The heat-loving plants need sun and well-drained soil. But gardeners can run into a few problems ranging from dark blemishes on blossoms and fruit to wilted and curled leaves. Some diseased plants carry certain viruses and should be discarded. However, troubleshoot problems first, before deciding your plants can't be saved.
Add lime. If you see a dark blemish at the blossom end of fruit, your soil is likely too acidic. Adding lime around the plants will raise the soil's pH levels. If you don't see improvement in one to two weeks, check for other sources of disease.
Grow fennel or dill near tomato plants. Plant leaves that look chewed usually mean you have tomato hornworm. Wearing gloves, handpick and destroy the worms. After harvesting the tomatoes, cultivate the soil to destroy any pupae or eggs.
Plant garlic or garlic chives among tomato plants if your plants have wilted and curled leaves. Aphids can be washed away by spraying your plants with water. The garlic repels the pests.
Remove infected plants. Pests such as aphids carry viruses. Avoiding the pest in the first place is the best way to ensure your plants are healthy. But if your plants appear stunted and leaves are mottled with a "shoestring" appearance, it's likely aphids have passed on the cucumber mosaic virus. Eliminate weeds and infected plants as soon as you notice this disease.
Use a pest and disease chart with photos to identify other problems. Other possible problems with tomato plants include bacterial canker, where leaves near the bottom of the plant turn brown and die; alternaria canker, which results in leaves browning and curling and can be controlled by fungicide sprays; and bacterial speck, which is seen as many brown specks on leaves.
Some treatments for pests and diseases such as bacterial canker mean having to remove and destroy the infected plant or plants. Other bacterial diseases, such as blight, leaf mold and bacterial speck, react well to purchased fungicide sprays.