20 



PEACH YELLOWS. 



In autumn, on several occasions, my father reported tbat some of the 

 inoculated trees had begun to look yellow and sickly. However, I did 

 not see them until July 1, 1889, i. e., one year from the previous ex- 

 amination and twenty three months from the insertion of the buds. 

 The change was then so great that I could scarcely credit my eyes, 

 With one exception, the uubudded trees continued healthy and had 

 made a good growth. On the other hand a very considerable number 

 of the inoculated trees were already dead, and most of the remainder 

 were in all stages of decline, dwarfed, yellow, and sickly. Evidently 

 some sort of virus was communicated by the inoculated diseased bud 

 to the previously healthy seedling, and this was probably transmitted 

 to all parts of the tree. At least, symptoms were visible to the very 

 extremities of the branches, 3 to 4 feet from the point of inoculation. 

 A few trees only had made a tolerable growth and seemed to be resist- 

 ing the evil influence. 



As in Experiment 1, here were the feeble, branched growths and the 

 winter buds germinating months in advance of the proper time. Again 

 there could be no question as to the nature of the disease. Some rep- 

 resentative photographs (plates xui-xvii) made July 1, 1889, show, 

 as well as can be done in black and white, the strikingly different 

 appearance of these two lots of trees. The exact conditions in August 

 were as follows : 



TABLE I. Resiilt of inoculations two years from the time the buds were inserted as shown 

 by comparison of budded and imbudded trees. 



From that day to this the contrast has become greater and greater 

 as the condition of the inoculated trees has gone on from bad to worse. 



The orchard was reexainiiied July 29-31, 1890, and another series of 

 photographs procured (plates xvm-xxiv). The condition of the in- 

 oculated trees was found to be much worse than last year. All which 

 were doubtful or seemed to be healthy in 1889 had become diseased, and 

 many more had died with the characteristic symptoms of the yellows. 

 Only two of the inoculated trees made any noteworthy growth in 1890, 

 and the best one of these two is shown in plate xvin, fig. 1. Of the 

 entire 219* trees which received diseased buds August 3, 1887, only 15 

 were living at the expiration of the third year. Nearly all of those 

 which died were more or less stunted and showed symptoms of yellows 

 either in the form of branching summer growths or of winter buds 

 which germinated in autumn. 



*Nine were rejected at time of planting on account of injuries received in digging. 

 The number 198 given in my Preliminary Report is a typographical error. 



