LIFE HISTORY OF THE MELON FLY 



By E. A. Back, Entomological assistant, and C. E. Pemberton. Scientific Assistant, 

 Mediterranean Fruit-Fly Investigations, Bureau of Entomology 



INTRODUCTION 



Aside from the Mediterranean fruit fly, Ceratitis capitata Wied., there 

 is no other insect in the Hawaiian Islands that is causing such financial 

 loss to fruit and vegetable interests as the melon fly, Bactrocera cucurbitae 

 Coq. The damages caused by its ravages are placed by some even higher 

 than those caused by C. capitata. While B. cucurbitae was not officially 

 recorded until November, 1898, when it was first discovered by Mr. George 

 Compere in the market gardens in the environs of Honolulu, it had been 

 knownlocally about that city many years before. Mr. Albert Waterhouse, 

 Acting President of the Hawaiian Board of Agriculture and Forestry, 

 states that less than 30 years ago excellent cantaloupes (Cucumis melo) 

 and watermelons {Citrullus vulgaris) and many kinds of pumpkins and 

 squashes were grown in profusion the year round. Since that time the 

 spread of the melon fly has been so rapid that this insect is now found on all 

 the important islands of the Hawaiian group, and cantaloupes and water- 

 melons can not be grown except on new land distant from old gardens. 

 More than 95 per cent of the pumpkin {Cu-curbita pepo) crop is annually 

 ruined, not to mention the havoc caused among the more resistant 

 cucumbers {Cucumis sativus). 



Not only does the adult melon fly oviposit in fruit that has already set, 

 but more often — in the case of the pumpkin and the squash {Cucurbita 

 spp.) — in the unopened male and female flowers, in the stem of the \ane, 

 and even in the seedUng itself, especially in seedlings of the watennelon 

 and the cantaloupe. The writers have observed entire fields of water- 

 melons killed before the plants were 6 to 8 inches long by larvae boring 

 into the taproot, stem, and leaf stalks. An examination of almost any 

 pumpkin or squash field in the agricultural districts on the Island of Oahu 

 at certain seasons of the year will show that very nearly all the flowers 

 are affected before they have an opportunity to bloom. In about 95 

 cases out of 100 the anthers of the male bloom are either reduced to a 

 mass of rot or more or less eaten before the bud becomes full grown, and 

 the young ovaries of the female bloom are ruined by the burrowing mag- 

 gots either before or shortly after the flower unfolds. 



While cucurbitaceous crops are the favored host fruits of the melon 

 fly, certain varieties of leguminous crops, such as string beans and cow- 

 peas, are often badly attacked. When preferred host fruits are scarce, 

 even peaches, papayas, and similar fruits are attacked to a limited degree. 

 No satisfactory remedy has yet been found to prevent the infestation of 

 fruit. The Chinese gardeners save a small percentage of crops subject to 

 the attacks of this pest by covering the young fruit with cloth or paper or, 

 in the case of the curcurbits, by burying them in the soil until they 

 become sufiiciently large to withstand attack. 



The female melon fly deposits her eggs in small batches just beneath 

 the surface of the fruit, vegetable, or plant affected. From these eggs 



Journal of AcTicuItiiral Research. Vol. Ill, No. 3 



Dept. of ApTicukiire, Wa^^hington. D. C. Dec 15 '1014 



(269) 



