10 



CIRCULAR 9 3 5, U. S. DEPARTMENT OF AGRICULTURE 



fruits harvested in 1947 and 1948 (tables 6 and 7). The apples used 

 for these studies were a part of those harvested for the bruising 

 investigations. 



Table 6. — Average diameter of blue mold decay lesions on punctured l 

 and inoculated Delicious apples at intervals of 15, 25, and 55 days 

 in 31° F. storage, harvest of 1947 



Maturity 



Average 

 firmness 



Average diameter of decay lesions after — 



15 days 



25 days 55 da}^s 



Early 



Medium 



Advanced _ _ 



Pounds 

 14. 9 ± 0. 19 

 14. 3 ±0. 18 

 12. 6±0. 38 



Centimeters 

 1. 62 ±0.04 

 1. 61 ±0. 05 

 1. 55 + 0. 05 



Centimeters 

 2. 38 ±0.05 

 2. 40 ±0. 05 

 2. 31 ±0. 04 



Centimeters 

 4. 64 ±0.04 

 4. 77 ± 0. 05 

 4. 55 ± 0. 06 











1 21 punctures were measured except on fruits of advanced maturity, on which 

 19 were measured. 



In 1948 immature and overmature apples from one tree were 

 punctured and inoculated at harvest and at intervals until March 21. 

 Measurements of diameters of the decayed areas were begun 10 days 

 after puncturing and inoculating (table 7). The immature apples 

 were held in storage until October 18 so that they could be punctured 

 and inoculated at the same time as the first of the overmature fruits. 



There was no relationship between the maturity of apples and the 

 rate of decav enlargement, once infection was established (tables 6 

 and 7). 



These findings are not in complete agreement with similar in- 

 vestigations by Baker and Heald (2). Their data indicated that 

 the rate of growth of blue mold was greater in Delicious apples of 

 prime maturity than in apples of early maturity. They stated, how- 

 ever, that the difference, although statistically significant, was slight, 

 and they were of the opinion that maturity was of small importance 

 in determining the internal resistance to decay expansion. 



Ripeness During Storage 



The rate of decay expansion remained the same throughout the 

 storage period regardless of the progressive ripening of the apples 

 (table 7). These results are in agreement with those of Baker and 

 Heald (2) for a storage period of 180 days. However, in their study 

 of decay-expansion rate in punctured and inoculated Delicious apples 

 during the storage period, they found that a marked advance of decay 

 enlargement rate occurred after a storage period of 180 days (approxi- 

 mately April 1). The increase in rate of expansion continued until 

 the end of the test period of 240 days. The present studies were 

 terminated with the March 21 series. 



