My Tomatoes Are Dying and the Leaves Are Curled

Curly Top Virus

• Look at the leaves that have started to curl. If they are the smaller leaflets instead of the larger leaves, and if they are turning purple, especially along the veins, and if the whole plant is becoming yellowish and growing slowly then you likely have a curly top virus infection. This infection is transmitted by the beet leafhopper insect. No chemical controls will prove effective. Prevent the leafhoppers from reaching healthy plants by covering them with row covers.

Fusarium Wilt

• If it is the larger, older leaves that are curling, and if they are doing so in a downward direction, you may have a problem with fusarium wilt. If this is the case, the affected leaves will also be turning yellow and the vascular tissue inside the stems will have turned a dark brown. This fungal infection is not controllable with available fungicides. Do not plant tomatoes in the affected area for three years after discovering a fusarium wilt infection. When you do plant them again, use seeds with an "F" in their codes. This means that they are resistant to the fungus.

Herbicide Damage

• If the leaves start curling soon after you have applied herbicide, you may very well have herbicide damage. Too much of it can burn and kill plants. Check your herbicide to make sure that you are applying the correct amount, or look into changing brands. Other symptoms indicating that the damage is caused by herbicides are stunting, leaves with a fern-like appearance or discolored centers.

Cucumber Mosaic Virus

• If no herbicide was recently applied but the plant growth is stunted, then you may have a problem with the cucumber mosaic virus. This can cause the plants to turn yellow or a mottled white. This virus usually means you have infected seeds, though people touching first one plant and then another can transmit the virus, as can aphids. Remove and destroy the infected plants.

Preventative Practices

• In general, you can keep your plants healthier in the long run by rotating your crops and keeping your garden free of debris from old plants. The longer the same plants or plant material are kept in the same place, the longer populations of fungi, insects, bacteria and viruses that prey on tomatoes can build up.