CHAPTER IV. 



PLANT-DISEASES, WITH PREVENTIVES AND 

 REMEDIES. 



As a general rule, all fungi wliicli attack the leaves 

 and cause them to become spotted, as the various leaf- 

 blights and mildews, are readily kept in check by 

 the thorough applications of fungicides. Fungi which 

 destroy the deeper tissues, as black-knot of plums and 

 red-rust of the quince, can also be kept off if the plant 

 is always covered with a fungicide. For the germ or 

 bacterial diseases, like pear-blight and others, there 

 are no specific preventives or remedies, and the horti- 

 culturist must resort to timely pruning, rotation of 

 crops, or various methods of strategy. 



The Bordeaux mixture is now considered to be the 

 best fungicide, but as it is essentially a whitewash 

 (colored with blue vitriol) it discolors fruits and 

 foliage. On ornamental plants, therefore, ammoniacal 

 carbonate of copper or modified eau celeste is prefer- 

 able. Upon fruits which are nearly full grown, the Bor- 

 deaux mixture may also be displaced by the other 

 fungicides, if it is necessary to spray at that period. 



Almond. Leaf-Blight or Almond Disease {Gercospora cir- 

 cunicissa, Sacc). — Attacks the foliage, making perfora- 

 tions and causing the leaves to fall. Serious in parts of 

 California. 



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