Tomato Diseases Gray Leaf Spot (Stemphylium solani, S. lycopersici)
Foliage of plants from seedlings to mature plant stage is affected. Brown to black specks appear on both the young and older leaves. The lesions expand slowly into 1- to 2-mm-diameter round spots that remain brown or develop a gray center surrounded by a yellow area. Sometimes the center of the spot dries and falls out, forming a shothole in the leaf. Lesions may be numerous, causing entire leaves to turn yellow, then brown and drop. Lesions rarely coalesce. Defoliation can be severe, leading to sunburn damage of the fruit. Similar lesions may occur, infrequently, on the younger stems and petioles. Fruit are not affected.