Notes on Certain Diseases of Plants Recently 



Observed 



BY W. C. STURGIS. PH.D. 



Sooty Spot of Apples. — Doubtless everyone who grows Rhode 

 Island Greenings or Newtown Pippins is familiar with the 

 appearance of fruit affected with this trouble. It is well illus- 

 trated in Plate I. The fungus causing it was described 

 by the writer in the Twenty-first Annual Report of the State 

 Experiment Station. It is a very widely spread trouble, occur- 

 ring in all localities and to a greater or less extent every year, 

 though its spread is naturally more rapid in a damp season 

 than when the weather is dry. Its effect upon the fruit is 

 entirely superficial, that is, it is limited to the skin of the 

 apple and does not penetrate or injure the flesh. It does, 

 however, render the fruit unsightly and therefore detracts 

 from its market value. 



This superficial habit of the fungus renders its control by 

 fungicides so simple a matter that it is astonishing that more 

 growers of apples do not adopt the practice of regular and 

 systematic spraying. As shown in the Report above referred 

 to, trees sprayed with Bordeaux mixture not only yielded a 

 larger crop of clean fruit than trees not sprayed, but the fruit 

 from the former showed that the fungicide acted as a preserv- 

 ative, the "keeping quality" of sprayed fruit being far superior 

 to that of the unsprayed fruit. 



The sooty spot occurs on many varieties of apples and 

 pears. 



Crown Gall of Peach. — This peculiar disease, illustrated in 

 Plate 2, is unquestionably on the increase in Connecticut. 

 It was not more than five years ago that my attention was first 

 called to it. To-day it can probably be found in every peach 

 orchard in the state. It is an insidious disease, working below 

 the surface, revealing its presence only in the gradual decline 

 of vigor on the part of its victim, not easily reached by fungi- 



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