Reserve 



MARCH, 1930 CORRECI 



ITED STATES DEPARTMENT OF AGiflCllL'^trkE 

 WASHINGTON, D. C. 



L I £? 



R E 



r^ V 



ED EDITION 



PARASITISM OF THE MEDITERRANEAN FRUIT FLY 

 IN HAWAII, 1922-1924 



By H. F. WiLLARD, Senior Entomologist, in Charge of Hawaiian Inspections, 

 'Plant Quarantine and Control Administration, and T. L. Bissell, Assistant 

 Entomologist, Division of Deciduous- Fruit Insects, Bureau of Entomology ^ 



CONTENTS 



Introduction 1 



Records of infestation 2 



Parasitism records :-- 4 



Page 



Summary 11 



Literature cited^ 12 



INTRODUCTION 



When the Mediterranean fruit fly {Ceratitis capitata Wiedemann) 

 arrived in Hawaii, where it was discovered in 1910, it found itself in 

 an almost ideal environment. Owing to a favorable climate, an 

 abundance and variety of host fruits, and a lack of natural enemies it 

 spread rapidly. The temperature range in littoral Hawaii is such 

 that this fly can reproduce rapidh^ during the w^hole year. It has 

 been shown by Back and Pemberton {3, p. 75)- that in the lower eleva- 

 tions of the islands 16 generations may be produced annually. There 

 have been recorded in Hawaii 73 different varieties of fruits and other 

 plants in which the Mediterranean fruit fly may reproduce, and at 

 all times during the year some of these varieties are in bearing and in 

 the proper condition for infestation. The species of insect enemies in 

 Hawaii that attacked it when it arrived w^ere so few and ineffective 

 that they had very little influence in checking its spread ; consequently, 

 within a short time after it was discovered there it had become 

 established upon all the larger islands of the Hawaiian group. 



The use of introduced insect parasites has been found a more prom- 

 ising control measure under the peculiar horticultural conditions of 

 Hawaii (where the majority of host fruits are either inedible or not 

 worth the cost of spraying) than are the artificial control methods of 

 sprajdng and the destruction of infested fruits employed in commercial 

 fruit-growing areas in certain other parts^f the world. In 1913 and 

 1914 the government of the Territory of Hawaii introduced and 

 established four species of parasites which attack the larval stage of 

 the fly. Three of the species were braconids and one a chalcid. Two 

 braconids, Opius humilis Silvestri and Diachasma Jullawayi Silvestri, 



1 At the time of the collecting of the information contained in this circular Mr. Willard was entomologist 

 and Mr. Bissell was plant quarantine inspector, both in the Division of Tropical, Subtropical, and Orna- 

 mental Plant Insects, Bureau of Entomology. 



^ Italic numbers in parentheses refer to "Literature cited," p. 12. 



275C— 30 



