1890-91.] PEACH YELLOWS. 209 



PEACH yp:llows. 



By W. R. Shaw, M.D, 

 [From the Biological Laboratory of the University of Toro?ito.] 



{Read 21st November, i8<pi.) 



Yellozvs is an infectious disease which occurs in almonds, nectarines, 

 apricots and peaches, in which it is characterized by particular lesions in 

 the fruit, foliage, development, and general appearance of the affected 

 tree. 



The duration of the disease is long, generally lasting over a period of 

 four years, and the name is derived from the yellowish appearance which 

 a tree in foliage assumes when so affected. 



The work having been done wholly in connection with peach trees, 

 our remarks are accordingly confined to the nature of the disease in 

 that particular class. 



It would be as well to style this subject not " peach yellows," but 

 " yellows in peaches," as you will see by the above that it is not peculiar 

 to that one particular fruit. 



These investigations were begun in the early part of the past summer 

 (1891J to find out if a cause could be discovered for the disease, and this 

 work has been pursued in the ordinary methods adopted for a bacterio- 

 logical investigation. It is of importance, both scientifically and from a 

 domestic point of view, and if by any means some light can be thrown 

 on the disease so that proper steps may be taken to stop its ravages, 

 then to my mind an important work has been done. 



It is to be regretted that the subject has not had more time for its 

 further consideration, but it being desirous to bring it as soon as possible 

 before the Canadian Institute in order that they may use their influence 

 for the proper means being adopted for the stamping out of the trouble, 

 I must present this as the apology for the present paper being in- 

 complete and simply a "preliminary report of the work." 



Before proceeding, a short resume of the history of this disease since 

 its first authentic description on this continent, would not be amiss, and 

 I am much indebted to the report of Mr. E. F. Smith, of the Depart- 



