118 BULLETIN 536, U. S. DEPARTMENT OF AGRICULTURE. 



determine the probable range of this pest should it be introduced and 

 gain a foothold in continental United States; (2) in verifying the 

 practicability of poison sprays; (3) in indicating the utilization of 

 cold-storage temperatures in making safe the movement of fruits 

 from areas which might otherwise be cut off by quarantines from 

 outside markets; and (4) in placing upon a sound basis the banana 

 and pineapple export trade of the Hawaiian Islands. 



At 50° F. little if any development takes place, and freezing tem- 

 peratures can be withstood successfully only for short periods. Ac- 

 cumulated data indicate that the Mediterranean fruit fly will not 

 become a serious pest in climates where the mean temperature is 

 below 50° F. during periods covering three months of the year. 



While Hawaiian conditions are unfavorable to the use of poison 

 sprays, the work of the writers has convinced them that these sprays 

 can be employed as successfully in combating this pest in commercial 

 orchards of California and of Southern States, should they ever 

 become infested, as in Africa and Australia. 



While at present cold storage is not utilized to modify existing 

 quarantine, it is a recognized fact that, commercially used, it has 

 been of value in safeguarding fruits from additional infestation while 

 en route over long distances. The data set forth herewith indicate 

 for the first time the duration of time required for various tempera- 

 ture ranges to kill the stages of the fruit fly within stored fruits, and 

 from these records it is reasonable to conclude that the certification 

 of properly refrigerated fruit is practicable. When an association of 

 fruit growers or the people discover that refrigeration is financially 

 worth while, there is reason to believe that it will result in the opera- 

 tion of central refrigeration plants under the supervision of officers 

 whose guarantee will insure that all fruits sent out from the plant are 

 absolutely free from danger as carriers of the Mediterranean fruit fly. 



