Grow Great-tasting Tomatoes

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Beyond food and water, tomato plants need to keep their leaves if they are to produce intensely flavorful fruits. “When you have a loss of foliage, you have a loss of flavor,” Gardner says

Insects are usually minor problems. Tomato hornworms are big enough to pick off by hand, and lots of other pests bypass tomatoes because they find them so unpalatable. At Ohio State University’s Organic Food and Farming Education and Research Center in Wooster, Sally Miller has evaluated more than a dozen natural pest-control products in tomato plots over the last three years. She has found that two products — Garlic Barrier, a garlic-based spray, and Trilogy, a neem oil extract — are effective for controlling insects that wander into the plots

Diseases are harder to control, because most are caused by fungi that live in the soil or that enter the garden as windblown spores. When you read seed catalogs, it’s hard not to be impressed by the long list of diseases for which genetic resistance is readily available. These symbols include “V” for verticillium wilt, a soil-borne fungus that causes plants to wilt and die; “F” for fusarium wilt, a soil-borne fungus that causes plants to turn yellow just before they wilt and die; “N” for parasitic nematodes that infest roots; “T” for tobacco mosaic virus, usually evidenced by oddly stringy leaves and malformed fruit; and a sprinkling of other letters for less-widespread diseases.

What’s been missing — until recently — are varieties resistant to early blight, a common leafspot disease that begins as dark spots on low leaves that become so numerous the leaves wither and fall. The good news is that a few varieties offer some resistance. A “saladette” variety with characteristically small, oblong fruits called ‘Plum Dandy’ is resistant, and Johnny’s Selected Seeds carries a round-fruited hybrid (cur-

rently known as JTO-99197) that has shown good resistance in the field. To manage early blight on nonresistant varieties, Miller has found that new bacterial fungicides, including Serenade (Bacillus subtilis) and Sonata (Bacillus pumilis), can reduce or delay foliar diseases when applied regularly to both sides of tomato leaves.

Unfortunately, no tomato can outgrow late blight, caused by ever- changing strains of the Phytopthora infestans fungus, the culprit behind the tragic Irish potato famine of the 19th century. At Oregon State University, breeders released the late blight-resistant ‘Legend’ determinate variety three years ago. ‘Juliet,’ an indeterminate, vigorous hybrid saladette, shows some resistance as well. But where disease pressure is high due to continuous cool, rainy weather, these varieties still succumb to the disease, too. This is not the tomato’s fault, because Phytopthora infestans has an amazing talent for changing the enzymes it uses to invade leaf tissues. “Anything you can do to reduce the introduction and spread of the pathogen will help,” says Jim Myers of Oregon State, who helped develop ‘Legend.’

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