By William Terry Kelley
University of Georgia
Most of the difficulty stems from a virus that afflicts tomatoes. Tomato spotted wilt has been in Georgia only a few years. It's a major problem for commercial growers in the Deep South, though. And it's truly the bane of garden tomatoes in that area.
If you've been growing garden tomatoes in Georgia over the past five to seven years, you've probably seen the virus.
How to recognize itThe symptoms vary, but young leaves usually turn bronze and later develop small, dark spots. The growing tips die back, and the stems of terminals may become streaked. Some plants may look one-sided or stunted overall.
Plants that get infected early usually don't develop fruit. The ones infected later may have knotty fruit. The more mature tomatoes may have light-colored ring spots, and green ones may have bumpy areas with faint, concentric rings. As these tomatoes mature, the rings get easier to see and turn red and white or red and yellow.
The bottom line is that you don't get any good tomatoes from infected plants.
How it spreadsThe disease is spread by thrips as they feed on the plant. And it's almost impossible to prevent infection by controlling these tiny insects. They usually transmit the virus before the insecticide can kill them.
Tomato spotted wilt has many hosts. It can infect crops such as peanuts, tobacco and pepper and countless weeds, too.
Commercial growers have ways to reduce the disease and its severity. Gardeners who try to grow tomatoes in a conventional garden have a hard time producing a harvestable crop.
Bottom lineSo, can you still grow garden tomatoes in the South? Yes, but you may have to change a few things about how you grow them.
As with almost any virus, the most effective way to control the virus is to use resistant varieties. A few are on the market now. You may have tried some of the earlier-released cultivars.
Not all resistant varieties are available to gardeners, though. The seeds of some come only in large quantities.
The seeds of some resistant varieties do come in small packets for gardeners, though. "Amelia," from Harris Seeds (www.harrisseeds.com), is one of the newest. Some seed companies offer "BHN 444" or "BHN 640" in small packages, too.
Look for plantsProbably the best way to get resistant varieties, however, is to look for seedlings at your favorite garden center. The seedlings may not be easy to find, but look for them.
One drawback to using these varieties is that they probably won't have quite the flavor of your old garden favorite. They were bred for commercial production. But let them get ripe on the vine and they'll be fine.
Another weapon that seems to help some commercial growers control the virus is using mulches. Planting tomatoes into black plastic mulch has been shown to reduce the level of infection over simple, bare-ground production.
Kitchen optionReflective silver mulches seem to work even better. These mulches have to be almost like chrome. Aluminum foil might make a suitable substitute, since the actual plastic, reflective mulches are expensive and hard to find.
Keeping weeds in check around the garden may help some, too. Some growers have even tried tying reflective streamers to the tomato stakes, with the idea that they confuse the thrips so they don't land on the tomatoes.
Growing tomatoes in home gardens isn't what it used to be. To keep those fresh, vine-ripe tomatoes coming, though, try these resistant varieties and changes in tactics. Hopefully, the days of growing home-garden tomatoes are far from numbered.
(Terry Kelley is an Extension Service horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.)
(Terry Kelley is a former University of Georgia Cooperative Extension horticulturist with the UGA College of Agricultural and Environmental Sciences.)