How to Prevent Tomato Blight

Purchase only healthy-looking plants. If you are starting your own tomatoes, do not use soil from last year's crop. Plant blight-resistant types of tomatoes.

Remove plant debris from your garden and burn it if allowed in your area. If you cannot burn it, place it in a plastic bag and seal it well for disposal. Do not compost diseased plant material.

Rotate your crops, planting tomatoes ideally at least 20 feet from where they were planted the year before.

Avoid overcrowding or over-watering your plants. Place stakes so that the plants can be tied up and kept off the ground. Proper air circulation helps to prevent fungus.

Keep the soil well cultivated and weeds removed. Remove suckers from tomato plants and remove any blighted leaves immediately.

Apply fungicide to the tomato plants according to the directions before the appearance of tomato blight. The spores are airborne. Avoid applying fungicide directly on red tomatoes.

Remove immediately a plant that shows signs of blight -- such as white, powdery spores and large olive green or brown spots on the leaves and stems. Seal it in a plastic bag and throw it away. Do not compost infected plants. Watch your other plants closely for signs.