DISEASES OF THE GRAPE 



1 



PROP. W. LOCH HEAD, ONT. 



^ HERE are several diseases which are 

 more or less commonly known in our 

 Ontario vineyards. The most common 

 disease this year has been the downy mil- 

 dew, or, locally known as brown rot. This 

 disease produces a thick white felt on the 

 under surface of the leaves, stems, and 

 fruit. The treatment outlined in this issue 

 for black rot will prevent the action of 

 downy mildew, but fewer sprayings may 

 be required. 



The bird's-eye rot or Anthracnose was 

 occasionally observed this season, but is not 

 doing much injury. It yields readily to 

 treatment by spraying, and should not be 

 feared when spraying is regularly practised. 

 It is important that the diseased wood should 

 be removed. 



Occasionally the powdery mildew does 

 some damage to our grape crop. It forms 

 a cobweb-like growth on the upper surfaces 

 of the leaves, and occasionally does con- 

 siderable harm to fruit. Spraying with the 

 Bordeaux will prevent injury from this dis- 

 ease. In spite of the presence of these pests 

 it is cl'ear that none of them can compare in 

 damage with the black rot, which is ex- 

 tremely difficult to control. 



the; mildews of grape. 



Regarding the mildews of grape, the 

 downy mildew, or the brown rot as it is 

 called in some districts, is by far the more 

 difficult to treat, inasmuch as the threads of 

 the fungus live within the tissues of the 

 plant, and only come to the surfaces to fruit. 

 Besides, a thick-walled winter spore is pro- 

 duced within the tissues of the leaf, and this 

 is very difficult to destroy unless measures 



I GROW A PEW STRAWBERRIES and find that 

 the Williams is the most productive, but that 

 Bubach is better in quality and more suit- 

 able for table use. I always put on a heavy 

 mulch of straw in the fall to protect the 

 plants in the winter. — (Dr. McCallum, 

 Smith's Falls, Ont. 



AGRI. COLLEGE, GUELPH. 



are taken to plow the leaves under deeply 

 or to burn them carefully. The powdery 

 mildew which forms the cobweb-like 

 growth on the upper surfaces of the leaves 

 and fruit was this summer the cause of con- 

 siderable destruction in the Grimsby dis- 

 trict. At one time it was supposed that 

 the cause of the rotting of the grapes in this 

 district was the downey mildew, but after 

 examination I found that the most abundant 

 fungus present on the leaves and fruit was 

 the powdery mildew. This is a surface- 

 feeding fungus and can readily be controlled 

 by frequent sprayings. 



The white rot, which Prof. Selby, of 

 Ohio, alludes to in one of his early bulletins, 

 is in all probability a phase of the black rot, 

 and he thinks he made a mistake when he 

 called it the white rot, for he has not been 

 able to find it in late years. 



Many of our fruit growers have come to 

 the conclusion that dust spraying would be 

 a very effective; method of dealing with the 

 fungous diseases of the orchard. They feel 

 that this method of applying a fungicide 

 could be used in weather which precludes 

 the liquid application. This view is not 

 held by Prof. Selby, who has had a great 

 deal of experience with spraying operations 

 and is one of our best informed authorities 

 on the diseases of grapes, as he be- 

 lieves dust spraying will never be as suc- 

 cessful as the liquid spray. The fine mist 

 produced, he believes, is far more penetrat- 

 ing than the fine dust of the dust sprayer. 

 Our orchard men should not run hastily 

 into the dust spraying before more is known 

 about its merits. 



In growing carnations I generally use p 

 top dressing of wood ashes and bone meal 

 mixed with soil. I put some salt and quite 

 a lot of lime in this. The salt serves as a 

 food for the carnations and also, prevents 

 rust. The lime acts as a combatant to in- 

 sect pests. — (H, Neal, Ingersoil, Ont. 



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