The Oidium appears sooner on poor soil and on exhausted vines, and vines in which the flow of the sap for some reason or other has been checked are more subject to the mildew than those which are yet in full growing vigor. Elevated vines on trellises which are much exposed, and vines which are so covered up that the air has little access, are the first ones to be attacked, and those which will suffer the most. The powdery mildew affects all varieties of grapes, but some kinds more than others. The Muscats are among those which suffer considerably, and if not sulphured would in severe cases neither set nor bear suitable grapes. The Malaga is less affected, and so is the Sultana. In new districts the Uncinula does not appear until the vines are older. Thus in the Fresno district the earliest vines did not suffer from mildew until they became five years old, but now the mildew would destroy the grapes every year, in case they were not treated with sulphur. _Remedies._--The most common and perhaps the best remedy is powdered sulphur. The latter is applied either with the dust can or “dredger,” or with bellows. The dust can is used when the vines or vine shoots are yet small, and the bellows when the vines are larger. The first sulphuring should be done when the young shoots are six inches long, immediately before the bloom, and the second time when the berries are well set. Sulphuring as a regular vineyard operation will be more fully discussed further on. DOWNY MILDEW OR PERONOSPORA.