Affected leaves develop small, dark brown spots that often grow in size, and which eventually kill the leaves. Gardens in central, southern and eastern states are most susceptible. Planting certified seed and mulching with hay can prevent this disease. You'll notice the disease first by water-soaked areas on the leaves that turn brown and black as the leaf dies. The disease strikes often during cool, wet weather and may spread rapidly if the weather warms up.
Plants can die in a severe case, and potatoes can be seriously affected, especially in storage.
Plant certified seed and use a potato dust to guard against late blight. Copyright 2000, National Gardening Association. All rights reserved. Click here to receive up to four Free estimates from prescreened and insured contractors. Easily Become a Master Gardener with Pre-Designed Gardens.