U. S. DEPARTMENT OF AGRICULTURE 



stressed avoidance of bruising. Baker and Heald (1 , pp. 26-27) 

 stated: 



During the past 2 years occasional apples have been seen that had one to many 

 lenticel infections on the margins of bruises and of flattened areas produced by 

 contact with the box or with other fruit. It is thought that localized pressure 

 may rupture the layer of cutinized cells in the lenticel basins and thus increase 

 susceptibility. 



The same authors in a later publication mentioned that the number 

 of infect ible lenticels was increased by bruising (2), and English and 

 his coworkers (.£) noted that many lenticel infections were found in 

 bruised areas. 



Preliminary tests (14) that demonstrated bruised areas of 

 Delicious apples were much more susceptible to blue mold decay 

 than nonbruised tissue, and contemporary investigations (7) that 

 disclosed the large numbers of bruises that occur in the harvesting 

 and packing operations, emphasized the need for further research on 

 the relation of bruising to subsequent decay. These investigations 

 were made during 1947, 1948, and 1949. 



Materials and Methods 



In order to study the influence of maturity on severity of bruising 

 and on the consequent blue mold infection in 1947, the required 

 numbers of Delicious apples were picked from 1 tree in each of 3 

 orchards. The early-maturity fruits were harvested at Monitor, 

 Wash., on September 19, the medium-maturity apples at Wenatchee 

 on September 22, and the advanced-maturity apples at Orondo on 

 September 29. 



The 1948 tests were designed to determine the influence of ma- 

 turity and ripeness on bruising damage and subsequent decay of 

 apples removed from storage at intervals during the storage season. 

 The apples for these investigations were harvested from one tree in 

 the Wenatchee area on September 21 and again on October 16. 



The 1949 studies of decay susceptibility of bruised tissue at various 

 intervals after bruising, and of the effect of cooling rate and storage 

 temperature on retardation of infection at bruises, were made on 

 apples of optimum maturity picked from one tree in the Wenatchee 

 area on September 26. 



Throughout the investigations the apples were carefully picked by 

 the writers to avoid the bruising incidental to commercial picking. 

 All fruits were placed in storage at 31° F. on the day picked. The 

 apples were then composited into separate lots for bruising or for 

 puncturing, inoculation, and pressure testing. 



Apple bruises are of various types, including small deep indenta- 

 tions caused by contact with picking-bag frames, numerous sharply 

 defined nicks or dents caused by the washing and packing equipment, 

 or flattened surfaces with varying depths of injured tissue that result 

 from rough dumping of boxes or pressure against the walls of the 

 package. Since it was not feasible to duplicate all types of bruises, 



