Controlling Tomato Diseases

There are a couple of different tomato diseases that can be very hard to control in the vegetable garden. However, if you know what causes these diseases and the symptoms behind them you can have better success with controlling and treating these pesky diseases. Depending on where you live you may experience more issues with certain diseases than somebody in a different area or zone.

Bacterial Wilt (aka Southern Bacterial Blight)

The main cause of bacterial wilt happens usually overnight and takes out two or three plants. This is a bacterial soil-borne disease that will happen when temperatures are humid and wet. One way to avoid bacterial wilt is by planting disease-resistant varieties such as Invincible. Another way to decrease your chance of avoiding this virus is to have at least a 3-year crop rotation. By implementing crop rotation in your garden you not only improve your soil health but also improve your chances of not dealing with these soil-borne tomato diseases. You should also remove crop debris as soon as those tomato plants are done producing. The quicker you remove all the crop debris from the area the faster those soil-borne diseases will be eliminated in the vegetable garden.

Early Blight

One of the more common tomato diseases that we hear a lot about is early blight. Early blight is caused by fungi that live in the soil and will start up when temperatures become hot and wet. You can identify early blight by looking for brown circular lesions on older foliage and yellowing of the plant tissue as well. The best way to treat early blight is to use drip irrigation to reduce leaf moisture, fertilize monthly with Calcium Nitrate, and treat plants with Mancozeb or Liquid Copper Fungicide.

Late Blight

Similar to early blight, late blight is also caused by fungi that live in the soil. However, late blight is triggered when temperatures become cooler and wetter in the vegetable garden. You can identify late blight on plants when dark and water-soaked spots pop-up on the tomato leaves. Once these spots become visible on the plants soon after the leaves will begin to fall off. The only late blight disease-resistant variety we have available is Invincible Tomato which is a determinate paste variety. Treating both early blight and late blight is very similar, you will need to use drip irrigation, remove crop debris, and use Liquid Copper Fungicide to help control this tomato disease. Also, the most common host for late blight is potatoes, therefore you need to have at least a 3 to 4-year crop rotation so you can avoid planting tomatoes after potatoes.

Septoria Leaf Spot (Gray Leaf Spot)

Septoria Leaf Spot is also known as Gray Leaf Spot is another fungal tomato disease. In order to identify gray leaf spot, the leaves will start forming tiny black specks or small circular spots with dark borders and a beige center. This tomato disease becomes problematic when temperatures reach 68 to 77 degrees and high humidity or heavy leaf moisture. We have several disease-resistant varieties such as Bella Rosa, Red Snapper, Summerpick, Mountain Vineyard, Big Beef, Florida 91, Invincible, Southern Ripe, Roadster, Jolene, Chef's Choice Pink, and Lemon Boy Tomato. Even though these varieties all have disease-resistance to gray leaf spot it does not mean they are 100% susceptible to getting this tomato disease.

Tomato Spotted Wilt Virus

When it comes to Tomato Spotted Wilt Virus this is spread by thrips that feed on the weeds in the garden. Once one plant gets this wilt virus it spreads quickly and spraying treatment is almost ineffective. Once the plants are infected they will be stunted with bronze or dark spots/p...