116 RATIONAL FRUIT CULTURE. 



of sulphur should be dusted over the leaves and shoots while 



damp. Mildew, easily recognised by the whitish powder on 



the foliage, is caused by excessive moisture, and lack of fresh 



air. Here, too, flowers of sulphur will be found useful. But 



in a heated house it is most effective when sprinkled on the 



pipes. This may be done for black rot and Grape rot, and for 



red spider. 



SHANKIN(;. 



It sometimes happens that the stalks of portions of the 

 bunches, or, in bad cases, of whole bunches, wither, the Grapes 

 in consequence shrivelling and turning brown. This is called 

 " shanking." It is not a disease; it is merely a sign that the 

 roots are unequal to the task which has been set them. Either 

 there is something wrong with the border in which they grow — 

 the soil may be exhausted, or excessively dry or wet, or they 

 may have got down into the subsoil — or the crop is too heavy 

 for them. The affected berries are naturally those which re- 

 ceive the smallest supply of food. If they are not the farthest 

 away from the sap-current — at the tips of the bunches — they 

 are badly placed for getting their fair share. The gardener 

 should set to work to discover the cause, and should remedy 

 it as soon as possible. The Grapes on the stalks which have 

 begun to wither cannot be saved, and should be cut out. 



