The mildew is our most formidable disease, and will very often sweep away two-thirds of a crop of Catawbas in a few days. It generally appears here from the first to the fifteenth of June, after abundant rains, and damp, warm weather. It seems to be a parasitic fungus, and sulphur applied by means of a bellows, or dusted over the fruit and vine is said to be a partial remedy. Close and early summer-pruning will do much to prevent it, throwing, as it does, all the strength of the vine into the young fruit, developing it rapidly, and also allowing free circulation of air. In some varieties--for instance, the Delaware--it will only affect the leaves, causing them to blight and drop off, after which the fruit, although it may attain full size, will not ripen nor become sweet, but wither and drop off prematurely. In seasons when the weather is dry and the air pure, it will not appear. It is most prevalent in locations which have a tenacious subsoil, and under-draining will very likely prove a partial preventive, as excess of moisture about the roots is no doubt one of its causes. The gray rot, or so-called grape cholera, generally follows the mildew, and I think that the latter is the principal cause of it, as I have generally found it on berries whose stems have been injured by the mildew. The berry first shows a sort of gray marbling; in a day or two it turns to a grayish-blue color, and finally withers and drops from the bunch. It will continue to affect berries until they begin to color, but only attack a few varieties--the Catawba, To Kalon, Kingsessing, and sometimes the Diana. The spotted, or brown rot, will also attack many of our varieties; it is very destructive to the Isabella and Catawba, and even the Concord is not quite free from it. But it is, after all, not very destructive, and not half as dangerous as the mildew or gray rot. Early and close summer-pruning is a partial preventative against all these diseases, as it will hasten the development of the fruit, allow free circulation of air, and the young leaves which appear on the laterals after pinching seem to be better able to withstand the effects of the mildew, often remaining fresh and green, and shading the fruit, when the first growth of leaves have already dropped.