188 AMBEICAlf POMOLOGY. 



handsome fruit, until, utterly exhausted, they reach a pro 

 mature end. 



Some varieties, that for many years yielded very fine, 

 crops of the most heautiful fruit, and of the highest char- 

 acter for flavor, have afterward ceased to furnish any per- 

 fect specimens — the whole crop being covered and de- 

 Tormed with the black scab or fungus, that prevents their 

 development, or else ruined by the disagreeable bitter-rot 

 which entirely spoils them for any use. Various remedies 

 have been suggested for these maladies, all of which are 

 more or less unsatisfactory, because from our ignorance of 

 the causes of the troubles ; these applications are wholly 

 empirical. 



The Black-knot, which has become very common in 

 some parts of the country, is well discussed by Benjamin 

 D. Walsh, in the Practical Entomologist, for March, 1866, 

 page 48. 



This essay is the more valuable because of the absence 

 of the empiricism just complained of: — 



" It is a black, puffy, irregular swelling on the twigs and 

 smaller limbs of plum and cherry trees, and, in one in- 

 stance that came under my personal observation of peach 

 trees, making its first appearance in the latitude of New 

 York early in June, and attaining its full growth by the 

 end of July. Usually a tree, that is attacked in this m.an- 

 ner, is affected worse and worse every year, until it is 

 finally killed ; and wherever one tree of a group is affect- 

 ed, the malady usually spreads to them all in process of 

 time. In 1863 wliole cherry orchards were destroyed la 

 Western New York by this disease, and I have myself seen 

 many groups of wild plum trees in Illinois that were gradu- 



