62 Journal of Agricultural Research voi. iv, no. i 



spring of 1914 from parts of two orchards in which the disease in pre- 

 vious years had not proved amenable to spraying. In one of these 

 orchards the part from which the cankers had been eradicated was the 

 section of the orchard in which during previous years bitter-rot had been 

 most destructive. The fruit of this part came through the season prac- 

 tically free from rot, while about 50 per cent of the fruit of the part from 

 which the cankers were not removed was destroyed by the disease. 

 Both of these parts were sprayed four times at intervals of two weeks, 

 beginning June 15. In the second orchard the fruit of neither plot was 

 sprayed, and all of it eventually rotted. In the plot in which the 

 cankers were allowed to remain every apple was infected by the middle 

 of July, whereas in the plot from which the cankers and dead wood had 

 been removed destruction was not complete until two months later. 

 Every apple in the untreated plot was evidently infected from primary 

 sources, since there were as yet no secondary sources. While an occa- 

 sional apple was found w^hich showed only i infection, nearly every one 

 of them showed at least 50 and many of them were literally covered 

 with the tiny, blister-like spots. In the treated plot early infections 

 were considerably less in number, and a majority of the fruit was free 

 from them. Later in the season, however, all fruit that had escaped the 

 early infections finally became infected from secondary sources. 



On May 15 a cankered limb from the second orchard was brought into 

 the laboratory and kept in a moist chamber for 24 hours. This canker 

 resembled in every way the limb cankers as described and figured by 

 Burrill and Blair and Von Schrenk and Spaulding (PI. VII, fig. 2). It 

 was a black, sunken, oval area, with many slight rifts or cracks in the 

 bark through which, after the limb had remained in a moist chamber for 

 24 hours, an abundance of the characteristic pink acervuli appeared. 

 Near the center of this canker was a small dead spur through which 

 infection probably took place. 



Cankers resembling in every way published descriptions and figures of 

 bitter-rot cankers were also collected on June 3 and many times thereafter. 



During the month of May there was collected from one of these orchards 

 a limb which was badly infected with Nuvimularia discreia, and while 

 spore masses of Glomerella cingulata were not abundant on it, yet enough 

 were present to make it a dangerous source of infection under proper 

 conditions. Later in the season spores were many times obtained from 

 Nummularia cankers. 



Spore masses of the fungus were also found on a long dead, well- 

 delimited part of a large limb in one of the orchards before mentioned. 

 This area was about 8 cm. wide and about 2 meters long. Wide cracks 

 along its margins sharply separated it from the living part of the limb 

 (PI. VII, fig. 3). Such strips of dead tissue are usually assigned to 

 injury by freezing or to the death of roots on one side of the tree. While 



