How to Keep My Tomato Plants From Getting Blight

Blight can be devastating to a tomato crop, but preventative measures can help.

Two diseases called "blight," both caused by fungi, may affect tomato plants. Early blight occurs in the spring and late blight occurs in late summer. Blight affects all visible parts of the plant, including stems, leaves and fruit. Brown or gray lesions on the stems or leaves, and discolored, bruised-looking spots on fruit are common symptoms of tomato blight. Blight can kill tomato plants and potato plants. To ensure a better harvest, you must keep an eye out for this disease and, preferably, take measures to prevent it.

Things You'll Need

• Fungicide for blight
• Rake

Instructions

1. Spray tomato plants with a fungicide that states on the label it is protective against tomato blight. Once a blight occurs, it is difficult to get rid of, so protective measures are your best bet. You may need to spray your plants more than once during the growing season, depending on the weather -- if it is rainy, the chance of blight is higher. Check the fungicide label for rate and frequency directions, as this can vary.

2. Rake up loose plant debris from around the tomato plants to keep the area clean and free of rotting organic matter. This should be done during the growing season, but also, in the fall, dead plants should be discarded and other plant debris raked up or turned under the soil to be covered. Doing this prevents fungal spores from thriving on decaying matter.

3. Water tomato plants in the early morning and at ground level, if possible, to avoid water contact with leaves. Using a sprinkler system, or otherwise watering the plants from overhead, may mean the leaves stay wet longer and encourage blight.

4. Plant your tomatoes in a different area of your garden at least every four years, but do not plant them in the same area that once contained potato plants as potato plants can also harbor blight.

References

• Iowa State University Extension; Tomato Diseases and Disorders; Mark L. Gleason and Brooke A. Edmunds
• Cornell University College of Agriculture and Life Sciences: Late Blight on Tomato
• The University of Maine Cooperative Extension: Early Blight of Tomato
• Colorado State University Extension: Tomato Early Blight