blight noun: 1. a plant disease, especially one caused by fungi such as mildews, rusts, and smuts. "the vines suffered blight and disease" Blight infects ornamental plants, vegetables, fruit trees, and shade trees worldwide. I am mainly going to focus on tomato and garden crop blight in this post. On tomatoes, potatoes, and peppers, it is called early blight. Blights are fungal diseases that are spread by spores in foggy, wet conditions. Spores overwinter on tomato and weed refuse in gardening beds, so it is important to rotate your crops to minimize the spread of blight. As a rule you should rotate your tomato plants, tomatoes seem to be easily hit with blight. Rule is spot A year one, three to 4 years later you can plant tomatoes again in spot A. Since blight lives in the soil, during wet conditions the soil will splash up onto the leaves. Its beginning stages effect the leaves, but its advanced stage can cause fruit rot and stem lesions. It is possible that the disease can spread to other plants like peppers and eggplant, but blight will not stop here. It can spread throughout your garden. Blight is in the soil so it is very important to treat your soil. When you first notice blight it is important to take steps to prevent spreading the disease. Very important, Blight spores can survive in the soil for three or four years. To treat your soil when blight is detected, this is the most natural way without using chemicals. 1 Remove all vegetation from the tomato garden bed and other suspected garden areas at the end of the growing season after you detect blight in tomatoes, potatoes or other nightshade plants. Dig into the soil to uproot the entire plant, and pick up pieces of broken stems, fallen tomatoes and other plant parts. 2 Place vegetation in plastic bags, seal them and throw them away immediately. 3 Deeply till the garden bed in late fall. Disrupting the soil prevents blight spores from having an undisturbed place to spend the winter. 4 Examine the entire garden in the spring before treating or planting the soil. Remove any additional vegetation that may harbor blight. Look for volunteer tomato plants that may have sprouted nearby, as well as other members of the nightshade family, such as remaining potato vines and tubers, pepper or eggplant vegetation, and the weed known as nightshade. 5 Place vegetation in plastic bags, seal them and throw them away immediately. 6 Spread 4-inch layers each of sand and compost over the soil, and work the layers into the top 6 to 9 inches of the existing garden bed. This step will not only improve drainage, but will help the soil warm up faster by raising the garden bed slightly higher than the surrounding soil. Higher, drier growing conditions are less hospitable to fungal spores. 7 Cover garden beds with white plastic mulch, which heats the soil, reducing humidity and killing blight spores still lingering in the garden. 8 Cover pathways with mulch such as wood chips. If you are not using white plastic on garden beds, mulch these areas as well. The mulch cuts down on the chances of blight reaching the plants through splashing mud. This info courtesy of How to Repair Soil With Tomato Blight | Home Guides | SF Gate Like mentioned earlier blight affects vegetables, fruit trees, and shade trees worldwide. Examples: Potato famine in Ireland Chestnut blight- devastated chestnuts throughout America starting early 1900's Corn blight and rice blight.