The Canadian Horticnltnrist. 



297 



Reply by II. T. (iallouuiy. Chic/ 0/ Section of Vegetable 

 l'atlioloi;y, Washington, D.C. 



The grapes are affected by what is 

 known as l^rown Rot, a form of 

 the downy mildew which attacks tlie 

 leaves. \\'e send you a description 

 of the disease. There is no doubt 

 that the Bordeaux mixture, if used 

 early enough in the season, will pre- 

 vent the ravages of this parasite 

 which seems to be the principal 

 grape trouble north of and including 

 New York state. 



(l.) — ^DOWNY MILDEW, BROWN AND 

 GREY- ROT, 



These diseases are caused by a 

 fungus known a.s Peronosporaviticola. 

 When the Pcrotiospora attacks the 

 leaves the disease is known as the 

 downy mildew ; when it attacks the 

 berries and destroys the pulp with- 

 out forming external reproductive 

 bodies it is brown-rot ; when it 

 occurs on the young fruit and covers 

 the berries with its greyish conidia or 

 " seed " grey-rot is the term applied 

 to it. 



Leaves affected with downy mil- 

 dew show, upon the upper surface, 

 greenish yellow or brownish spots of 

 irregular size and shape, while op- 

 posite these discolorations, on the 

 lower side, a downy, whitish, frost- 

 like growth may be seen. In ad- 

 vanced stages of the disease, or after 

 a heavy rain, the frost-like patches 

 often disappear, leaving in their 

 place light brown discolorations cor- 

 responding in size and shape with 

 those on the upper side. 



Brown-rot usually appears when 

 the fruit is nearly full-grown and, as 

 already stated, there is no external 

 evidence of the presence of a fungus. 

 Purplish brown discolorations appear 

 as a first manifestation of this form 

 of rot. Soon the entire berry turns 

 brown, the pulp becomes soft and 

 often shrinks, forming depressions, 

 over which the wrinkled yet other- 

 wise smooth and unbroken skin is 

 stretched. 



In the case of grey-rot the berries 

 and often the pedicel are covered 

 with a frost-like growth similar to 

 that which occurs on the leaves. In 

 fact the characters of this disease 

 are so well marked that a further 

 description is useless as it cannot 

 well be mistaken for anything else. 



(11.) — THE POWDERY MILDEW. 



This mildew usually makes its 

 appearance toward the middle of 

 summer and continues until frost. 

 It attacks the leaves, young shoots 

 and fruit, covering them with a pow- 

 dery meal-like growth altogether 

 different from the downy mildew, 

 also differs from the latter in that it 

 occurs abundantly on the upper sur- 

 face of the leaves where it forms 

 mealy white patches of various sizes 

 and shapes. Occasionally it is 

 spread out quite evenly over the 

 entire surface, resembling in some 

 respects the delicate web of a spider. 

 Fruit affected with the powdery 

 mildew shows on the surface a coat- 

 ing of whitish, meal-like dust; this 

 rapidly increases in thickness and 

 soon the berries shrivel, the skin 

 cracks, admitting other agents of 

 decay, which soon finish the work of 

 destruction. 



Wine Making. 



78. Would you kindly answer the follow- 

 ing question in your excellent publication, 

 viz., how to make a fair quality of wine from 

 say from 3 or 4 (,'allons of grape juice? I 

 have good receipts for large (juantities with 

 proper appliances but not in small quantities. 

 I have made a good wine from red and white 

 currants in small lots. — A. J. Collins, I.is- 

 tou'cl. 



In reply to our correspondent we 

 cannot do better than to give the fol- 

 lowing quotation from an exchange : 



*' The grapes are allowed to ripen 

 well before being gathered, when the 

 juice is expressed and bottled im- 

 mediately. The bottles are filled 

 to the brim ami then placed, up to 



