210 THE GEAPE 0ULTUBI8T. 



liaMe to it than those that have never been attacked. When 

 the vines are planted too thickly, either in the house or 

 open air, they are more or less liahle to be attacked by 

 mildew. Anything that tends to weaken the plants — like 

 a cold soU, sudden changes of weather, or extremes of heat 

 or cold, several cloudy days in succession, followed by 

 bright sunshine, or a few days of cold weather, will usually 

 weaken young plants sufficiently to render them liable to 

 be attacked. ' 



To prevent mildew get good strong plants of healthy 

 varieties, plant them upon a warm soil, and then train 

 them, whether young or old, so that the light and air may 

 reach every leaf. Also, allow no greater number of shoots 

 or leaves to be produced than can be fuUy developed. A 

 free circulation of air is desirable, but cold northern winds 

 are to be avoided. If these directions are strictly followed, 

 but little injury will result from mildew, even upon those 

 varieties that are generally supposed to be more or leas 

 affected. 



SUN SCALD. 



This is another disease, produced mainly by "sudden 

 changes of the atmosphere, although the natural unhealth- 

 iness of the plant may have something to do with it. 

 There are but few of our native varieties that suffer much 

 from sun scald, and usually it is those that have soft leaves 

 with a feeble texture. The Isabella is a variety that prob- 

 ably has been more affected by this disease than any 

 other, and it is more prevalent in this vicinity and south- 

 ward than farther north. It usually makes its appearance 

 after a few cloudy damp days, especially if they are follow- 

 ed by very hot clear weather. 



The leaves seem to become blistered or burnt, sometimes 

 the whole leaf will be destroyed, and others will be only 

 affected in spots. That portion injured will turn brown, 

 and in a few days it becomes dry and crisp. K the leaves 



