MEDITERRANEAN ERUIT FLY IN HAWAII. 41 



fusion of other fruit-fly species, known definitely to attack bananas, with C. capitata. 

 Illingworth, in 1913, reared the banana fruit fly {Dacus curvipennis Frogg.) from 

 larvae taken in Sydney from bananas imported from Suva. Lea, in Tasmania in 1908, 

 thoroughly familiar with the Mediterranean fruit fly as a result of the campaign for its 

 eradication about Launceston, states that the Queensland fruit fly (Dacus tryoni Frogg.) 

 only was found in bananas imported into Tasmania, and does not list this fruit among 

 the host fruits of C. capitata. Broun states that, in 1906, Dacus tryoni was the only 

 fruit fly reared from bananas imported during February and March into New Zealand 

 from Fiji and Rarotonga. In the report of the biologist of Western Australia in 1898 

 we read that a consignment of 50 cases of bananas supposed to have originated in 

 Fiji, but more likely having been transhipped to Sydney from an original source in 

 Queensland, had been destroyed at Freemantle because found infested by the Queens- 

 land fruit fly. Quinn, in 1907, writes "after seven years experience with bananas 

 * * * we have not yet found the maggots in green bananas. If green when arriv- 

 ing here (South Australia) , how very green indeed must they have been when cut from 

 the trees about three weeks previous." French, of Victoria, appears to be the only 

 person in Australia who definitely makes the statement that he has reared C. capitata 

 from bananas exported from Queensland into Victoria. Yet Tryon, of Queensland, 

 in a conversation with the senior writer in 1913, stated that C. capitata had never been 

 taken in the banana fields of Queensland. The inclusion of the banana among the 

 fruits infested by C. capitata and intercepted at the entry ports of New Zealand by 

 Kirk seems to have been an editorial error, as already pointed out in the paper on the 

 banana as a host referred to below. From the foregoing references, it is possible to 

 assume that the results obtained by the writers in Hawaii, where fruit-fly attack is as 

 severe as anywhere, will be verified when opportunity is presented for such careful 

 experiments in other countries as the commercial value of this fruit warrants. Because 

 of the controversial statements of French and Severin it is desirable that Australian 

 entomologists publish data secured in field experiments. 



Those particularly interested in the status of the banana as a host fruit are referred 

 to a paper 1 already published by the writers, giving experimental data from which the 

 following conclusions were drawn: 



Since the Mediterranean fruit fly (Ceratitis capitata Wied.) ^as not been found 

 infesting the Chinese banana (Musa cavendiskii) or the Bluefield banana (Musa sp.) 

 during the three years that the Federal Government has had charge of the inspec- 

 tion of export bananas in the Hawaiian Islands, it is evident that some reason exists 

 for this practical immunity. This is the more apparent since adult flies of both sexes 

 have been found present in all parts of banana plantations, and surrounding fruits 

 known to be hosts have been heavily infested. 



This immunity is shown to be due to the fact that neither the egg nor the nearly 

 hatched larva of the fruit fly can survive in the tannin-laden peel of green, though 

 mature, fruit. In fact, the copious and sudden flow of sap from egg punctures made 

 by fruit flies in unripe bananas renders the successful deposition of eggs in such fruits 

 difficult and rare. 



The fact that not 1 of 1,044 fruits of the dninese banana ripening singly and pre- 

 maturely among bunches growing in the field, and upon which, as in the case of 

 other host fruits, one might expect gravid females to concentrate their attention for 

 the purpose of oviposition, has been found to be infested, leads to the conclusion 

 that even ripe bananas are not desired as host fruits by adult fruit flies under Hawaiian 

 conditions. _ On the other hand, the rearing of flies from the ripe and yellow fruits of 

 the thin-skinned Popoulu variety, as well as from ripe fruits of other varieties under 

 forced and unnatural conditions, leads to the equally acknowledged fact that ripe 

 bananas in the field may serve as hosts and should therefore be properly guarded 

 against in all quarantine work. 



From the facts stated, the writers believe that bunches of any variety of bananas 2 

 now growing in the Hawaiian Islands, when properly inspected for the removal of 



1 Back, E.A., and Pemberton, C. E. Banana as a host fruit of the Mediterranean fruit fly. Jour. 

 Agr. Research, v. 5, p. 793-804. 1916. , 



2 As an added precaution against the spread of C. capitata to the mainland, cooking bananas of all 

 types are excluded from the trade. 



