MEDITERRANEAN FRUIT FLY IN HAWAII. 101 



While it seems evident that the favored host fruits of C. capitata 

 will always be well infested if present cultural conditions persist, it is 

 hoped that the value of the parasites may be sufficiently enhanced to 

 free from attack such fruits as the avocado pear, which at present is 

 infested just at the stage at which it becomes fit for harvesting. 



The general effectiveness of parasite control will be increased 

 with the discovery and introduction of a suitable egg parasite. 



ARTIFICIAL CONTROL. 



The only method employed at the present time in Hawaii satis- 

 factorily to protect fruits from attack of the Mediterranean fruit fly 

 is the covering of the fruits while they are still too green to be affected. 

 The value of the use of cold storage as a method of rendering fruits 

 already harvested free from danger as carriers of the pest has been 

 demonstrated, but cold storage, of course, can have no bearing on the 

 activities of the fruit fly in the orchard. No satisfactory substance 

 has yet been discovered for trapping adult females, and the killing 

 of adults of both sexes by poison sprays is not a feasible method of 

 control in Hawaii under present cultural conditions any more than is 

 the destruction of the immature stages by the burial, submergence, 

 burning, or boiling of the infested host fruits. The exceptional con- 

 ditions found in Hawaii make impracticable at the present time the 

 application of any of these field methods of control, except that of 

 covering the young fruit, notwithstanding the fact that the value of 

 these control measures when they can be consistently, intelligently, 

 and universally applied, has been demonstrated. 



PROTECTIVE COVERINGS. 



The only certain method now known of protecting fruits from attack 

 by the Mediterranean fruit fly is to cover them when still quite young 

 with some type of covering through which the female will not deposit 

 eggs. During 1898 Fuller reports that about 22,000 running yards 

 of mosquito netting were imported into South Africa for use in 

 covering trees to protect the fruit from fruit-fly attack. The cloth 

 was sewed into bags sufficiently large to be slipped over the trees and 

 tied about the trunk. This method has been employed by the writers 

 in protecting ripening peaches. Care must be taken, in Hawaii at 

 least, to place the bags over the trees when the fruits are very small 

 or early infestations will have already occurred which, after the cover- 

 ings have been placed, will produce generations of adults that will 

 result in the infestation of the entire crop beneath the covering. 



Covering the entire tree is too expensive to be followed out on a 

 large scale, and entirely impractical with large trees or in windy areas. 

 Protecting fruits with individual coverings made of cloth or paper is 

 more popular in Hawaii. Fruits inclosed in paper bags are well 



