CHAPTER IV. 



PLANT DISEASES, 



WITH PREVENTIVES AND REMEDIES. 



Apple. BITTER-ROT (Glceosporium fructigenum, Berk.). 

 A dry rot appearing in patches on many varieties of ap- 

 ples, and extending some distance into the tissue. 



No remedies or preventives are known. 

 BROWN-ROT. See under Cherry. 



POWDERY MILDEW (Podosphcera oxycanthcz, DeBary). At- 

 tacks nursery stocks, covering leaves with a grayish and 

 powdery meal-like mildew. 



Remedy. Ammoniacal carbonate of copper, applied four 

 or five times. 



RUST (species of Rcestelia}. Bright yellow rust J appearing 

 on the young leaves and fruit, causing the whole tree to 

 become enfeebled. It is now known that one stage of this 

 fungus is the "cedar apple" which grows on red cedars 

 and junipers, where it is known as Gymnosporangium. 

 Several species have been described. 



Preventive. Destroy the cedars or keep them free from 

 the "apples." Destroy hawthorns and escaped apples, 

 which are liable to be infested. Some varieties of apples 

 appear to be more susceptible to injury than others. 

 SCAB {Fusicladiuni dentriticum, Fckl.). Brown or blackish 

 scab-like spots on the leaves and fruit, arresting growth 

 and causing the parts to become distorted. 



Remedy. Spray with soda hyposulphite or potassium 

 sulphide, several times during June and July. Sulphide 

 of soda wash. 

 Apricot. LEAF- RUST. See under Plum. 



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