Growing tomatoes can be difficult, but well worth effort

By By Steve Strong / area extension horticulture agent
May 5, 2004
Tomatoes are the all-time favorite vegetable planted in Southern gardens, grown for their flavor, for health benefits like lycopene, and often just to compete with the next door neighbor. Being tops in the garden also makes tomatoes the target of a number of disease pests that require a variety of methods to combat.
Different diseases attack specific parts of the plants, and the most common are those that attack the foliage like Early Blight fungus. Early Blight appears shortly after the plants are put in the ground, beginning as yellow bleached spots on the lower leaves, and progressing upward during the growing season in a pattern described as "firing up."
Leaf spots caused by fungi and bacteria can be managed with early repeat applications of an approved garden fungicide, using products that contain chlorothalonil or a copper-based compound. Reduce foliage disease problems with proper plant spacing to provide better air circulation, and avoid overhead watering to keep leaves as dry as possible.
Southern Blight or white mold, is a fungus that attacks stems at the ground level, producing masses of cottony white growth with dark brown "mustard seed" spores enclosed. This is a hot weather pathogen that can be simply prevented at planting time by wrapping the stem at the soil line with a 5 inch-wide strip of aluminum foil (to reflect sunlight).
Other diseases
Other diseases that live in the soil are not so easy to manage, like Fusarium Wilt that kills plants by entering roots and attacking the vascular tissue inside. Fusarium is a slow, progressive wilt that often affects only one side of the plant, and is best prevented by planting disease resistant varieties, and practicing crop rotation every three to five years.
Crop rotation is used for related families of vegetables (tomato, pepper, and eggplant) that all fall prey to the same pests, especially those that live in the soil. Rotating related crops to other areas of the garden every few years (switching rows of peas and beans with squash-melon-cucumber plots) removes the food source that soil diseases need to survive.
Bacterial wilt is a prime example, a quick killer that strikes overnight, looking like a jealous neighbor poured boiling water on top of the plants. This soil disease cannot be cured with any known type of chemical other than sterilization fumigants (requiring a special permit), so crop rotation is one of the only ways to combat the problem.
Deep tilling
Deep tilling of 4 to 5 feet, or removal of the entire garden soil are a couple of desperate measures for disease control, but an easier option is to create raised beds. Containers also overcome poor soil drainage or recurring pest problems disinfect used pots before replanting with a 10 percent bleach solution, and always use fresh growing media.
Soil "solarizing" is another effective way to reduce soil disease and insect pests, and even nuisance weeds like nutgrass. Solarization kills pests by trapping the sunlight's heat and energy underneath a clear sheet of plastic covering. This is best done when the garden is fallow for six to eight weeks in July and August; make sure to waterlog the area first and then cover the edges of plastic sheeting for the proper "boil-in-bag" results.
On a final note, tomato fruit can also have problems, particularly blossom-end rot caused by calcium deficiency rather than an actual disease. Maintain even soil moisture during fruit ripening, and soil test before planting to determine the correct lime to provide calcium and a soil pH of about 6.5.
Check with the county Extension Service office at 482-9764 for more information on soil sampling and garden pest control. Visit the Mississippi State University Web site at www.msucares.com to download a copy of the Garden Tabloid, Publication 1091, for all the dirt that's fit to print on growing vegetables.