MORTALITY OF APPLE MAGGOT IN FRUIT IN STORAGE 9 



more, with the incidence of the rotting a question is raised as to how 

 much of the mortalit}^ produced could be attributed to the tempera- 

 ture and how much to the rot. 



After the completion of larval emergence, each fruit of the lots held 

 45, 50, 60, and 70 days was examined internally for the possible pres- 

 sence of pupae. Only two partially transformed larvae were located 

 and both of these were dead. 



SUMMARY 



Many foreign countries prohibit the importation of apples showing 

 any degree of infestation by the apple maggot (Rhagoletis pomonella 

 (Walsh) ) . Studies were therefore made to determine the possible use 

 of cold storage as a disinfesting agent for fruit intended for sale in 

 foreign markets. Fruit was placed in refrigeration rooms held at 

 temperatures of approximately 32°, 36°, and 40° F. 



Complete mortality of apple maggot eggs and larvae was effected 

 within 32 days at an air temperature of 32° F. and within 45 days 

 at 36°. 



Larval progress through the fruit appeared to stop in storage 

 temperatures of 32° and 36° F., but continued slowly at 40°, although 

 all but a few individuals eventually died. 



Since the air movement in the storage chamber was limited to that 

 induced by gravity, the temperature of the fruit in the interior of the 

 package remained nearly 1° F. above air temperature. 



In commercial cold storages kept at approximately 32° F., 40 days 

 should provide ample time for equalization of fruit and air tempera- 

 tures, as well as for complete mortality, and allow a margin of safety. 



