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SULPHATE OF IRON (COPPERAS OR GREEN VITRIOL.) 



Against anthracnose of the grape the following application has 

 shown itself to be of great value, and it is regularly used by 

 European vineyardists. 



Water, (hot), 100 parts. 



Iron sulphate, as much as the water will dissolve. 



Sulphuric acid, I part. 



Great care should be exercised in using this preparation, as it 

 is exceedingly caustic and will injure machinery, clothes, and 

 nearly everything with which it comes in contact. It is generally 

 applied with a swab made by tying rags about the end of a stick. 

 Dormant vines are uninjured by the treatment. 



UNEXPLAINED DISEASES. 



The unexplained diseases of the Vine are important enough to 

 merit special notice, as they have been the subject of many inves- 

 tigations. As a general conclusion of the perusal of some of the 

 more important results obtained, we are led to regard most of the 

 unexplained diseases as " physiological," that is, they are due to 

 defects in cultivation, to adverse climatic or other conditions, and 

 to the use of unsuitable varieties of the Vine. Fungi or insects 

 may appear along with diseases of this kind, but they come later 

 and only because the plants are already weakly. One might even 

 go further, and say that most of the fungus-diseases of the Vine 

 are really started by defects in cultivation : the Vines are weak- 

 ened, the fungi come and complete the mischief. 



The methods employed to produce a large supply of fruit of high 

 quality may easily result in conditions favourable to the develop- 

 ment of disease. 



SHANKING. 



"Shanking" is a trouble which accompanies grape-growing all 

 over the world. The grapes as they approach maturity fall off the 

 bunch, breaking away where the stalk joins the fruit ; or they may 

 simply shrivel up and remain attached. The grapes to go first are 

 those towards the lower end of a bunch, or those on the shoulders. 



The number may vary from one to many, and the trouble may 

 be apparent all over the vine or only on parts of it. The foliage 

 is at the same time more or less affected ; generally the leaves 

 turn brown and curl in places, or all over. Insects or fungi have 

 never been proved to be the real cause of the trouble, the chief 

 reason is to be sought in the condition of the vine itself. No 

 doubt, the disease is not always due to the same cause. Over- 

 cropping frequently leads to " shanking," so, also, does too early 

 ripening of the wood. Both of these conditions result in a drain 

 on the food-supplies which the plant has to provide, and will lead 

 to starvation of maturing fruit. Excessive moisture and heat pro- 

 duce conditions favourable to " shanking " if they cause undue 

 forcing of the vines ; on the other hand, any check due to sudden 

 dryness or cooling will be first seen in the fruit bunches. 



