422 STATE HORTICULTURAL SOCIETY. 



not make its appearance until the berries are nearly grown. At this time 

 a brownish purple spot will appear on one side of the berry and in a short 

 time the whole fruit is involved, turning brown and ultimately becoming 

 soft and wrinkled. The skin usually remains unbroken until the berry 

 drops to the ground, which it does at the slightest touch or jar. In gray 

 rot the fruit is covered with the same frost-like growth seen on the leaves. 

 The berries are literally plastered together with the fungus, the effect 

 being so peculiar and so different from any other disease that no one will 

 fail to recognize it. 



Poivdery mildew. — This usually appears about midsummer, attacking the 

 leaves, young wood, and berries. Occasionally, however, it appears earlier 

 in the season and in such cases is often very destructive to the flowers. It' 

 forms on the various parts attacked a powdery, mealy growth, this being 

 very marked on the leaves, where it is usually more abundant upon the 

 upper surface. The berries attacked often crack, exposing the seed in a 

 very peculiar manner. Upon close examination of any part of the vine 

 affected with powdery mildew, fine, delicate threads which make up the veg- 

 etative portion of the fungus may be seen. This in itself is enough to 

 distinguish the disease from downy mildew, the only malady for which it is 

 likely to be mistaken. 



Black rot. — Black rot is so widespread and well known that it is hardly 

 necessary to describe it. It may be well, however, to call attention to the 

 fact that the disease usually appears first on the leaves and young shoots,, 

 causing reddish brown or blackish spots. Ten or fifteen days later the 

 berries are attacked, the first evidence of this being a black or brownish 

 spot at one or more points on the surface. Soon the whole berry turns 

 brown, then black, and finally becomes hard and leathery, but as a rule 

 clings firmly to its stalk. 



Anthracnose. — Like the downy mildew and black rot, anthracnose 

 attacks the leaves, growing shoots, and young berries. 



Leaves, when first affected with the disease, show minute blackish brown 

 spots, which are surrounded with a slightly raised, darker-colored margin. 

 Ultimately the centers of the spots turn gray, and not infrequently the 

 diseased parts crack across or separate from the surrounding healthy por- 

 tions, leaving the leaf full of small, ragged holes. On the shoots, the dis- 

 ease manifests itself in much the same way as it does on the leaves. As it 

 progresses, however, the spots usually become darker at their center, and 

 often run together, forming more or less elongated diseased areas which 

 gradually eat their way into the wood. The scars made in this way may 

 often be seen on the ripened wood, and it is now known that the mycelium 

 or body of the fungus passes the winter in the tissues surrounding these 

 places. 



Anthracnose on the fruit, or bird's-eye rot, as it is sometimes called, 

 first appears as a blackish or brown circular spot, surrounded by a narrow, 

 somewhat darker rim. As the spots increase in size the color undergoes 

 various changes. In some cases the outside rim remains dark brown, 

 while inside of this is a wider zone of a beautiful vermillion color sur- 

 rounding a grayish center. Frequently the spots, when less than one 

 eighth of an inch in diameter, assume a grayish-white color, which they 

 retain throughout the rest of their growth. When the berries are small 

 the disease often manifests itself in another way. The fruit turns brown, 

 shrivels up, and, at the same time, little pinkish pustules appear on the 



