MEDITERBANEAN FRUIT FLY IN HAWAII. 



79 



This conclusion drawn from cold-storage experiments 1 will be 

 found, the writers believe, to hold true for out-of-door conditions. 

 During January to March, 1914, the writers exposed infested apples 

 on the slopes and summit of the extinct volcano Hualalai, at eleva- 

 tions of about 5,000 and 8,250 feet. At about 5,000 feet elevation, 

 where the temperature ranged from 31° to 64° F., during January, 

 with a mean of about 51° F., the larval development was apparently 

 held at a standstill, although as the minimum temperatures increased 

 with the approach of spring, larvae were able to more than hold their 

 own. During March, when the daily temperatures ranged from 40° 

 to 70° F., with a mean of about 55° F., development of all stages 

 occurred attended by no unusual mortality. At 8,250 feet elevation, 

 where the minimum temperatures ranged from 27° to 43° F., with the 

 maximums between 42° and 70° F., and a mean for the maximums and 

 minimums of about 48° F., no development took place. Instead, the 

 mortality was very great. As spring approached, the temperatures 

 increased until, during March 20 to 25, they ranged between 38° and 

 67° F. The result of examinations made of infested apples after 

 indicated periods of exposure are given in Table XXIII. 



Table XXIII. — Mortality among eggs and.larvse of the Mediterranean fruit fly in apples 

 exposed on the summit of Hualalai from Jan. 31 until date of removal. 





Date of 

 examina- 

 tion. 



Eggs un- 

 hatched. 



Larvae. 



Fruit removed from 

 mountain. 



First instar. 



Second instar. 



Third instar. 





Alive. 



Dead. 



Alive. 



Dead. 



Alive. 



Dead. 



Feb. 4 



Feb. 5 

 Feb. 15 

 Feb. 19 

 Feb. 26 

 Mar. 6 

 Mar. 19 

 Mar. 27 





221 



334 



3 



27 



55 



3 



1 



1 

 20 

 115 

 350 

 481 

 315 

 872 











Feb. 12 





522 

 97 

 37 

 33 



82 



16 



434 



216 



278 

 56 



33 

 2 

 3 





Feb. 17 



5 

 28 



10 

 2 

 24 





Feb. 25 



154 







Mar. 17 



6 

 2 



500 



Mar. 26 



2 



965 







These data prove that at the Hualalai temperatures a very few 

 larvae may survive, although by far the largest percentage are killed. 



The data given elsewhere (p. 108-111) on the effect of cold storage 

 and freezing temperatures upon the various stages of the fruit fly prove 

 how easily this pest can withstand for short intervals colder tem- 

 peratures than are likely to occur for long periods in fruit-fly coun- 

 tries. Thus the egg itself has been known to withstand a freezing 

 temperature of from 24° to 30° F. for 7 days and still hatch. These 

 low temperatures, however, produce a very great mortality that has 

 been emphasized by data already published. 



That adverse climatic conditions have been a valuable aid in curb- 

 ing fruit-fly attack is appreciated by entomologists dealing with this 



i See Journal of Agricultural Research, v. 5, 1916, p. 657-666; v. 6, 1916, p. 251-260. 



