SOURCES OF APPLE BITTEE-EOT IISTFECTIONS. 5 



Von Schrenk and Spaulding (13) in 1903, after investigations 

 carried on. in Missouri, state — 



Another source of infection is found in tlie dried mummies lianging on the 

 trees and lying on the ground under the trees. The diseased apples of one 

 season either fall to the ground (most of them do) or they remain on the trees, 

 where they dry and shrivel up. When examined in the. spring many of these 

 mummified fruits are found to contain spores of the bitter-rot fungus in 

 quantity. 



Again they state — 



It was formerly supposed that the fungus passed the winter in the mummies, 

 but as most of these were on the ground it was diflicult to understand how the 

 apples high up in the trees became infected. It now seems probable that the 

 mummies play a comparatively small part in serving as distributing points for 

 spores from year to year. 



In 1902, Alwood (1), as the result of observations and experiments 

 in Virginia, came to the conclusion that the mummied fruits on the 

 tree and the rotted fruits on the ground were the chief sources of 

 infection. He states — 



It appears to be well established that the mummied fruits hanging to the 

 trees and the rotten fruits upon the soil constitute in large measure the source 

 of the annually recurring infection. To my mind these fruits are the source 

 of infection. 



Scott (14, p. 12) in 1906, in his discussion of sources of infection, 

 states — 



The results [of observations made in Virginia and West Virginia orchards] 

 lead to the conclusion that the overwintering mummies hanging on the trees 

 constitute the chief source of infection, at least in this particular region. In 

 the majority of cases examined, a nuimmy could be found in the upper portion 

 of the infected area. 



Burrill (3) in 1907 considered that mummies on the ground rarely 

 acted as infection sources. 



The writer (10) in 1915, as the results of investigations in the 

 Ozarks of Arkansas, stated — 



Masses of spores were also obtained many times from mummies, and where 

 mummies are present tliey undoubtedly are important sources of infection. In 

 many of the badly infected orchards, however, they had been removed both from 

 the trees and from the ground. 



It will be noted that eastern investigators consider mummied and 

 rotted fruits as the principal means by which the fungus is carried 

 over from season to season. Investigators working in the Middle 

 West, however, consider them as of only secondary importance in 

 the survival of the fungus through the winter. 



The writer during the past three years has examined mummied 

 and rotted fruits of previous seasons from orchards in Virginia and 

 in Arkansas. In both mummies and rotted fruits of the preceding 



