8 



CIRCULAR 600, U. S. DEPT. OF AGRICULTURE 



lots was on the average further developed than that in the controls at 

 the time the fruit was placed on the larval emergence rack; that is, the 

 larvae grew while in storage. The occurrence of mortality might 

 seem to complicate this evidence. Nevertheless, up to the twentieth 

 day of the emergence period, more larvae emerged per 100 fruits from 

 the 40° lots held 10, 15, 20, and 24 days than from the controls. 



r- 25 



25 



O 5 10 15 20 25 30 35 



DURATION OF EMERGENCE (DAYS) 



Figure 4. — Duration and rate of emergence of apple maggot larvae from various 

 lots following exposure of the fruit to refrigeration: A, For 10 days at 32° and 

 40° F. ; B, for various periods at 40°. 



It was necessary to terminate the experiment at the end of the 

 seventieth day, and, as may be seen in table 1, this storage period 

 was insufficient to destroy all larvae. Had it been possible to obtain 

 records extending beyond 70 days, it seems doubtful whether any data 

 of practical significance would have been gained. Many of the fruits 

 had rotted by this time and the remainder soon would have. Further- 



